summaryrefslogtreecommitdiffstats
path: root/kernel/locking/lockdep.c
blob: c0e31bfee25c2ab0cfefef14b9e24e2ce8a5c523 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380
2381
2382
2383
2384
2385
2386
2387
2388
2389
2390
2391
2392
2393
2394
2395
2396
2397
2398
2399
2400
2401
2402
2403
2404
2405
2406
2407
2408
2409
2410
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424
2425
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438
2439
2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459
2460
2461
2462
2463
2464
2465
2466
2467
2468
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488
2489
2490
2491
2492
2493
2494
2495
2496
2497
2498
2499
2500
2501
2502
2503
2504
2505
2506
2507
2508
2509
2510
2511
2512
2513
2514
2515
2516
2517
2518
2519
2520
2521
2522
2523
2524
2525
2526
2527
2528
2529
2530
2531
2532
2533
2534
2535
2536
2537
2538
2539
2540
2541
2542
2543
2544
2545
2546
2547
2548
2549
2550
2551
2552
2553
2554
2555
2556
2557
2558
2559
2560
2561
2562
2563
2564
2565
2566
2567
2568
2569
2570
2571
2572
2573
2574
2575
2576
2577
2578
2579
2580
2581
2582
2583
2584
2585
2586
2587
2588
2589
2590
2591
2592
2593
2594
2595
2596
2597
2598
2599
2600
2601
2602
2603
2604
2605
2606
2607
2608
2609
2610
2611
2612
2613
2614
2615
2616
2617
2618
2619
2620
2621
2622
2623
2624
2625
2626
2627
2628
2629
2630
2631
2632
2633
2634
2635
2636
2637
2638
2639
2640
2641
2642
2643
2644
2645
2646
2647
2648
2649
2650
2651
2652
2653
2654
2655
2656
2657
2658
2659
2660
2661
2662
2663
2664
2665
2666
2667
2668
2669
2670
2671
2672
2673
2674
2675
2676
2677
2678
2679
2680
2681
2682
2683
2684
2685
2686
2687
2688
2689
2690
2691
2692
2693
2694
2695
2696
2697
2698
2699
2700
2701
2702
2703
2704
2705
2706
2707
2708
2709
2710
2711
2712
2713
2714
2715
2716
2717
2718
2719
2720
2721
2722
2723
2724
2725
2726
2727
2728
2729
2730
2731
2732
2733
2734
2735
2736
2737
2738
2739
2740
2741
2742
2743
2744
2745
2746
2747
2748
2749
2750
2751
2752
2753
2754
2755
2756
2757
2758
2759
2760
2761
2762
2763
2764
2765
2766
2767
2768
2769
2770
2771
2772
2773
2774
2775
2776
2777
2778
2779
2780
2781
2782
2783
2784
2785
2786
2787
2788
2789
2790
2791
2792
2793
2794
2795
2796
2797
2798
2799
2800
2801
2802
2803
2804
2805
2806
2807
2808
2809
2810
2811
2812
2813
2814
2815
2816
2817
2818
2819
2820
2821
2822
2823
2824
2825
2826
2827
2828
2829
2830
2831
2832
2833
2834
2835
2836
2837
2838
2839
2840
2841
2842
2843
2844
2845
2846
2847
2848
2849
2850
2851
2852
2853
2854
2855
2856
2857
2858
2859
2860
2861
2862
2863
2864
2865
2866
2867
2868
2869
2870
2871
2872
2873
2874
2875
2876
2877
2878
2879
2880
2881
2882
2883
2884
2885
2886
2887
2888
2889
2890
2891
2892
2893
2894
2895
2896
2897
2898
2899
2900
2901
2902
2903
2904
2905
2906
2907
2908
2909
2910
2911
2912
2913
2914
2915
2916
2917
2918
2919
2920
2921
2922
2923
2924
2925
2926
2927
2928
2929
2930
2931
2932
2933
2934
2935
2936
2937
2938
2939
2940
2941
2942
2943
2944
2945
2946
2947
2948
2949
2950
2951
2952
2953
2954
2955
2956
2957
2958
2959
2960
2961
2962
2963
2964
2965
2966
2967
2968
2969
2970
2971
2972
2973
2974
2975
2976
2977
2978
2979
2980
2981
2982
2983
2984
2985
2986
2987
2988
2989
2990
2991
2992
2993
2994
2995
2996
2997
2998
2999
3000
3001
3002
3003
3004
3005
3006
3007
3008
3009
3010
3011
3012
3013
3014
3015
3016
3017
3018
3019
3020
3021
3022
3023
3024
3025
3026
3027
3028
3029
3030
3031
3032
3033
3034
3035
3036
3037
3038
3039
3040
3041
3042
3043
3044
3045
3046
3047
3048
3049
3050
3051
3052
3053
3054
3055
3056
3057
3058
3059
3060
3061
3062
3063
3064
3065
3066
3067
3068
3069
3070
3071
3072
3073
3074
3075
3076
3077
3078
3079
3080
3081
3082
3083
3084
3085
3086
3087
3088
3089
3090
3091
3092
3093
3094
3095
3096
3097
3098
3099
3100
3101
3102
3103
3104
3105
3106
3107
3108
3109
3110
3111
3112
3113
3114
3115
3116
3117
3118
3119
3120
3121
3122
3123
3124
3125
3126
3127
3128
3129
3130
3131
3132
3133
3134
3135
3136
3137
3138
3139
3140
3141
3142
3143
3144
3145
3146
3147
3148
3149
3150
3151
3152
3153
3154
3155
3156
3157
3158
3159
3160
3161
3162
3163
3164
3165
3166
3167
3168
3169
3170
3171
3172
3173
3174
3175
3176
3177
3178
3179
3180
3181
3182
3183
3184
3185
3186
3187
3188
3189
3190
3191
3192
3193
3194
3195
3196
3197
3198
3199
3200
3201
3202
3203
3204
3205
3206
3207
3208
3209
3210
3211
3212
3213
3214
3215
3216
3217
3218
3219
3220
3221
3222
3223
3224
3225
3226
3227
3228
3229
3230
3231
3232
3233
3234
3235
3236
3237
3238
3239
3240
3241
3242
3243
3244
3245
3246
3247
3248
3249
3250
3251
3252
3253
3254
3255
3256
3257
3258
3259
3260
3261
3262
3263
3264
3265
3266
3267
3268
3269
3270
3271
3272
3273
3274
3275
3276
3277
3278
3279
3280
3281
3282
3283
3284
3285
3286
3287
3288
3289
3290
3291
3292
3293
3294
3295
3296
3297
3298
3299
3300
3301
3302
3303
3304
3305
3306
3307
3308
3309
3310
3311
3312
3313
3314
3315
3316
3317
3318
3319
3320
3321
3322
3323
3324
3325
3326
3327
3328
3329
3330
3331
3332
3333
3334
3335
3336
3337
3338
3339
3340
3341
3342
3343
3344
3345
3346
3347
3348
3349
3350
3351
3352
3353
3354
3355
3356
3357
3358
3359
3360
3361
3362
3363
3364
3365
3366
3367
3368
3369
3370
3371
3372
3373
3374
3375
3376
3377
3378
3379
3380
3381
3382
3383
3384
3385
3386
3387
3388
3389
3390
3391
3392
3393
3394
3395
3396
3397
3398
3399
3400
3401
3402
3403
3404
3405
3406
3407
3408
3409
3410
3411
3412
3413
3414
3415
3416
3417
3418
3419
3420
3421
3422
3423
3424
3425
3426
3427
3428
3429
3430
3431
3432
3433
3434
3435
3436
3437
3438
3439
3440
3441
3442
3443
3444
3445
3446
3447
3448
3449
3450
3451
3452
3453
3454
3455
3456
3457
3458
3459
3460
3461
3462
3463
3464
3465
3466
3467
3468
3469
3470
3471
3472
3473
3474
3475
3476
3477
3478
3479
3480
3481
3482
3483
3484
3485
3486
3487
3488
3489
3490
3491
3492
3493
3494
3495
3496
3497
3498
3499
3500
3501
3502
3503
3504
3505
3506
3507
3508
3509
3510
3511
3512
3513
3514
3515
3516
3517
3518
3519
3520
3521
3522
3523
3524
3525
3526
3527
3528
3529
3530
3531
3532
3533
3534
3535
3536
3537
3538
3539
3540
3541
3542
3543
3544
3545
3546
3547
3548
3549
3550
3551
3552
3553
3554
3555
3556
3557
3558
3559
3560
3561
3562
3563
3564
3565
3566
3567
3568
3569
3570
3571
3572
3573
3574
3575
3576
3577
3578
3579
3580
3581
3582
3583
3584
3585
3586
3587
3588
3589
3590
3591
3592
3593
3594
3595
3596
3597
3598
3599
3600
3601
3602
3603
3604
3605
3606
3607
3608
3609
3610
3611
3612
3613
3614
3615
3616
3617
3618
3619
3620
3621
3622
3623
3624
3625
3626
3627
3628
3629
3630
3631
3632
3633
3634
3635
3636
3637
3638
3639
3640
3641
3642
3643
3644
3645
3646
3647
3648
3649
3650
3651
3652
3653
3654
3655
3656
3657
3658
3659
3660
3661
3662
3663
3664
3665
3666
3667
3668
3669
3670
3671
3672
3673
3674
3675
3676
3677
3678
3679
3680
3681
3682
3683
3684
3685
3686
3687
3688
3689
3690
3691
3692
3693
3694
3695
3696
3697
3698
3699
3700
3701
3702
3703
3704
3705
3706
3707
3708
3709
3710
3711
3712
3713
3714
3715
3716
3717
3718
3719
3720
3721
3722
3723
3724
3725
3726
3727
3728
3729
3730
3731
3732
3733
3734
3735
3736
3737
3738
3739
3740
3741
3742
3743
3744
3745
3746
3747
3748
3749
3750
3751
3752
3753
3754
3755
3756
3757
3758
3759
3760
3761
3762
3763
3764
3765
3766
3767
3768
3769
3770
3771
3772
3773
3774
3775
3776
3777
3778
3779
3780
3781
3782
3783
3784
3785
3786
3787
3788
3789
3790
3791
3792
3793
3794
3795
3796
3797
3798
3799
3800
3801
3802
3803
3804
3805
3806
3807
3808
3809
3810
3811
3812
3813
3814
3815
3816
3817
3818
3819
3820
3821
3822
3823
3824
3825
3826
3827
3828
3829
3830
3831
3832
3833
3834
3835
3836
3837
3838
3839
3840
3841
3842
3843
3844
3845
3846
3847
3848
3849
3850
3851
3852
3853
3854
3855
3856
3857
3858
3859
3860
3861
3862
3863
3864
3865
3866
3867
3868
3869
3870
3871
3872
3873
3874
3875
3876
3877
3878
3879
3880
3881
3882
3883
3884
3885
3886
3887
3888
3889
3890
3891
3892
3893
3894
3895
3896
3897
3898
3899
3900
3901
3902
3903
3904
3905
3906
3907
3908
3909
3910
3911
3912
3913
3914
3915
3916
3917
3918
3919
3920
3921
3922
3923
3924
3925
3926
3927
3928
3929
3930
3931
3932
3933
3934
3935
3936
3937
3938
3939
3940
3941
3942
3943
3944
3945
3946
3947
3948
3949
3950
3951
3952
3953
3954
3955
3956
3957
3958
3959
3960
3961
3962
3963
3964
3965
3966
3967
3968
3969
3970
3971
3972
3973
3974
3975
3976
3977
3978
3979
3980
3981
3982
3983
3984
3985
3986
3987
3988
3989
3990
3991
3992
3993
3994
3995
3996
3997
3998
3999
4000
4001
4002
4003
4004
4005
4006
4007
4008
4009
4010
4011
4012
4013
4014
4015
4016
4017
4018
4019
4020
4021
4022
4023
4024
4025
4026
4027
4028
4029
4030
4031
4032
4033
4034
4035
4036
4037
4038
4039
4040
4041
4042
4043
4044
4045
4046
4047
4048
4049
4050
4051
4052
4053
4054
4055
4056
4057
4058
4059
4060
4061
4062
4063
4064
4065
4066
4067
4068
4069
4070
4071
4072
4073
4074
4075
4076
4077
4078
4079
4080
4081
4082
4083
4084
4085
4086
4087
4088
4089
4090
4091
4092
4093
4094
4095
4096
4097
4098
4099
4100
4101
4102
4103
4104
4105
4106
4107
4108
4109
4110
4111
4112
4113
4114
4115
4116
4117
4118
4119
4120
4121
4122
4123
4124
4125
4126
4127
4128
4129
4130
4131
4132
4133
4134
4135
4136
4137
4138
4139
4140
4141
4142
4143
4144
4145
4146
4147
4148
4149
4150
4151
4152
4153
4154
4155
4156
4157
4158
4159
4160
4161
4162
4163
4164
4165
4166
4167
4168
4169
4170
4171
4172
4173
4174
4175
4176
4177
4178
4179
4180
4181
4182
4183
4184
4185
4186
4187
4188
4189
4190
4191
4192
4193
4194
4195
4196
4197
4198
4199
4200
4201
4202
4203
4204
4205
4206
4207
4208
4209
4210
4211
4212
4213
4214
4215
4216
4217
4218
4219
4220
4221
4222
4223
4224
4225
4226
4227
4228
4229
4230
4231
4232
4233
4234
4235
4236
4237
4238
4239
4240
4241
4242
4243
4244
4245
4246
4247
4248
4249
4250
4251
4252
4253
4254
4255
4256
4257
4258
4259
4260
4261
4262
4263
4264
4265
4266
4267
4268
4269
4270
4271
4272
4273
4274
4275
4276
4277
4278
4279
4280
4281
4282
4283
4284
4285
4286
4287
4288
4289
4290
4291
4292
4293
4294
4295
4296
4297
4298
4299
4300
4301
4302
4303
4304
4305
4306
4307
4308
4309
4310
4311
4312
4313
4314
4315
4316
4317
4318
4319
4320
4321
4322
4323
4324
4325
4326
4327
4328
4329
4330
4331
4332
4333
4334
4335
4336
4337
4338
4339
4340
4341
4342
4343
4344
4345
4346
4347
4348
4349
4350
4351
4352
4353
4354
4355
4356
4357
4358
4359
4360
4361
4362
4363
4364
4365
4366
4367
4368
4369
4370
4371
4372
4373
4374
4375
4376
4377
4378
4379
4380
4381
4382
4383
4384
4385
4386
4387
4388
4389
4390
4391
4392
4393
4394
4395
4396
4397
4398
4399
4400
4401
4402
4403
4404
4405
4406
4407
4408
4409
4410
4411
4412
4413
4414
4415
4416
4417
4418
4419
4420
4421
4422
4423
4424
4425
4426
4427
4428
4429
4430
4431
4432
4433
4434
4435
4436
4437
4438
4439
4440
4441
4442
4443
4444
4445
4446
4447
4448
4449
4450
4451
4452
4453
4454
4455
4456
4457
4458
4459
4460
4461
4462
4463
4464
4465
4466
4467
4468
4469
4470
4471
4472
4473
4474
4475
4476
4477
4478
4479
4480
4481
4482
4483
4484
4485
4486
4487
4488
4489
4490
4491
4492
4493
4494
4495
4496
4497
4498
4499
4500
4501
4502
4503
4504
4505
4506
4507
4508
4509
4510
4511
4512
4513
4514
4515
4516
4517
4518
4519
4520
4521
4522
4523
4524
4525
4526
4527
4528
4529
4530
4531
4532
4533
4534
4535
4536
4537
4538
/*
 * kernel/lockdep.c
 *
 * Runtime locking correctness validator
 *
 * Started by Ingo Molnar:
 *
 *  Copyright (C) 2006,2007 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
 *  Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra
 *
 * this code maps all the lock dependencies as they occur in a live kernel
 * and will warn about the following classes of locking bugs:
 *
 * - lock inversion scenarios
 * - circular lock dependencies
 * - hardirq/softirq safe/unsafe locking bugs
 *
 * Bugs are reported even if the current locking scenario does not cause
 * any deadlock at this point.
 *
 * I.e. if anytime in the past two locks were taken in a different order,
 * even if it happened for another task, even if those were different
 * locks (but of the same class as this lock), this code will detect it.
 *
 * Thanks to Arjan van de Ven for coming up with the initial idea of
 * mapping lock dependencies runtime.
 */
#define DISABLE_BRANCH_PROFILING
#include <linux/mutex.h>
#include <linux/sched.h>
#include <linux/sched/clock.h>
#include <linux/sched/task.h>
#include <linux/sched/mm.h>
#include <linux/delay.h>
#include <linux/module.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/spinlock.h>
#include <linux/kallsyms.h>
#include <linux/interrupt.h>
#include <linux/stacktrace.h>
#include <linux/debug_locks.h>
#include <linux/irqflags.h>
#include <linux/utsname.h>
#include <linux/hash.h>
#include <linux/ftrace.h>
#include <linux/stringify.h>
#include <linux/bitops.h>
#include <linux/gfp.h>
#include <linux/kmemcheck.h>
#include <linux/random.h>
#include <linux/jhash.h>

#include <asm/sections.h>

#include "lockdep_internals.h"

#define CREATE_TRACE_POINTS
#include <trace/events/lock.h>

#ifdef CONFIG_PROVE_LOCKING
int prove_locking = 1;
module_param(prove_locking, int, 0644);
#else
#define prove_locking 0
#endif

#ifdef CONFIG_LOCK_STAT
int lock_stat = 1;
module_param(lock_stat, int, 0644);
#else
#define lock_stat 0
#endif

/*
 * lockdep_lock: protects the lockdep graph, the hashes and the
 *               class/list/hash allocators.
 *
 * This is one of the rare exceptions where it's justified
 * to use a raw spinlock - we really dont want the spinlock
 * code to recurse back into the lockdep code...
 */
static arch_spinlock_t lockdep_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;

static int graph_lock(void)
{
	arch_spin_lock(&lockdep_lock);
	/*
	 * Make sure that if another CPU detected a bug while
	 * walking the graph we dont change it (while the other
	 * CPU is busy printing out stuff with the graph lock
	 * dropped already)
	 */
	if (!debug_locks) {
		arch_spin_unlock(&lockdep_lock);
		return 0;
	}
	/* prevent any recursions within lockdep from causing deadlocks */
	current->lockdep_recursion++;
	return 1;
}

static inline int graph_unlock(void)
{
	if (debug_locks && !arch_spin_is_locked(&lockdep_lock)) {
		/*
		 * The lockdep graph lock isn't locked while we expect it to
		 * be, we're confused now, bye!
		 */
		return DEBUG_LOCKS_WARN_ON(1);
	}

	current->lockdep_recursion--;
	arch_spin_unlock(&lockdep_lock);
	return 0;
}

/*
 * Turn lock debugging off and return with 0 if it was off already,
 * and also release the graph lock:
 */
static inline int debug_locks_off_graph_unlock(void)
{
	int ret = debug_locks_off();

	arch_spin_unlock(&lockdep_lock);

	return ret;
}

unsigned long nr_list_entries;
static struct lock_list list_entries[MAX_LOCKDEP_ENTRIES];

/*
 * All data structures here are protected by the global debug_lock.
 *
 * Mutex key structs only get allocated, once during bootup, and never
 * get freed - this significantly simplifies the debugging code.
 */
unsigned long nr_lock_classes;
static struct lock_class lock_classes[MAX_LOCKDEP_KEYS];

static inline struct lock_class *hlock_class(struct held_lock *hlock)
{
	if (!hlock->class_idx) {
		/*
		 * Someone passed in garbage, we give up.
		 */
		DEBUG_LOCKS_WARN_ON(1);
		return NULL;
	}
	return lock_classes + hlock->class_idx - 1;
}

#ifdef CONFIG_LOCK_STAT
static DEFINE_PER_CPU(struct lock_class_stats[MAX_LOCKDEP_KEYS], cpu_lock_stats);

static inline u64 lockstat_clock(void)
{
	return local_clock();
}

static int lock_point(unsigned long points[], unsigned long ip)
{
	int i;

	for (i = 0; i < LOCKSTAT_POINTS; i++) {
		if (points[i] == 0) {
			points[i] = ip;
			break;
		}
		if (points[i] == ip)
			break;
	}

	return i;
}

static void lock_time_inc(struct lock_time *lt, u64 time)
{
	if (time > lt->max)
		lt->max = time;

	if (time < lt->min || !lt->nr)
		lt->min = time;

	lt->total += time;
	lt->nr++;
}

static inline void lock_time_add(struct lock_time *src, struct lock_time *dst)
{
	if (!src->nr)
		return;

	if (src->max > dst->max)
		dst->max = src->max;

	if (src->min < dst->min || !dst->nr)
		dst->min = src->min;

	dst->total += src->total;
	dst->nr += src->nr;
}

struct lock_class_stats lock_stats(struct lock_class *class)
{
	struct lock_class_stats stats;
	int cpu, i;

	memset(&stats, 0, sizeof(struct lock_class_stats));
	for_each_possible_cpu(cpu) {
		struct lock_class_stats *pcs =
			&per_cpu(cpu_lock_stats, cpu)[class - lock_classes];

		for (i = 0; i < ARRAY_SIZE(stats.contention_point); i++)
			stats.contention_point[i] += pcs->contention_point[i];

		for (i = 0; i < ARRAY_SIZE(stats.contending_point); i++)
			stats.contending_point[i] += pcs->contending_point[i];

		lock_time_add(&pcs->read_waittime, &stats.read_waittime);
		lock_time_add(&pcs->write_waittime, &stats.write_waittime);

		lock_time_add(&pcs->read_holdtime, &stats.read_holdtime);
		lock_time_add(&pcs->write_holdtime, &stats.write_holdtime);

		for (i = 0; i < ARRAY_SIZE(stats.bounces); i++)
			stats.bounces[i] += pcs->bounces[i];
	}

	return stats;
}

void clear_lock_stats(struct lock_class *class)
{
	int cpu;

	for_each_possible_cpu(cpu) {
		struct lock_class_stats *cpu_stats =
			&per_cpu(cpu_lock_stats, cpu)[class - lock_classes];

		memset(cpu_stats, 0, sizeof(struct lock_class_stats));
	}
	memset(class->contention_point, 0, sizeof(class->contention_point));
	memset(class->contending_point, 0, sizeof(class->contending_point));
}

static struct lock_class_stats *get_lock_stats(struct lock_class *class)
{
	return &get_cpu_var(cpu_lock_stats)[class - lock_classes];
}

static void put_lock_stats(struct lock_class_stats *stats)
{
	put_cpu_var(cpu_lock_stats);
}

static void lock_release_holdtime(struct held_lock *hlock)
{
	struct lock_class_stats *stats;
	u64 holdtime;

	if (!lock_stat)
		return;

	holdtime = lockstat_clock() - hlock->holdtime_stamp;

	stats = get_lock_stats(hlock_class(hlock));
	if (hlock->read)
		lock_time_inc(&stats->read_holdtime, holdtime);
	else
		lock_time_inc(&stats->write_holdtime, holdtime);
	put_lock_stats(stats);
}
#else
static inline void lock_release_holdtime(struct held_lock *hlock)
{
}
#endif

/*
 * We keep a global list of all lock classes. The list only grows,
 * never shrinks. The list is only accessed with the lockdep
 * spinlock lock held.
 */
LIST_HEAD(all_lock_classes);

/*
 * The lockdep classes are in a hash-table as well, for fast lookup:
 */
#define CLASSHASH_BITS		(MAX_LOCKDEP_KEYS_BITS - 1)
#define CLASSHASH_SIZE		(1UL << CLASSHASH_BITS)
#define __classhashfn(key)	hash_long((unsigned long)key, CLASSHASH_BITS)
#define classhashentry(key)	(classhash_table + __classhashfn((key)))

static struct hlist_head classhash_table[CLASSHASH_SIZE];

/*
 * We put the lock dependency chains into a hash-table as well, to cache
 * their existence:
 */
#define CHAINHASH_BITS		(MAX_LOCKDEP_CHAINS_BITS-1)
#define CHAINHASH_SIZE		(1UL << CHAINHASH_BITS)
#define __chainhashfn(chain)	hash_long(chain, CHAINHASH_BITS)
#define chainhashentry(chain)	(chainhash_table + __chainhashfn((chain)))

static struct hlist_head chainhash_table[CHAINHASH_SIZE];

/*
 * The hash key of the lock dependency chains is a hash itself too:
 * it's a hash of all locks taken up to that lock, including that lock.
 * It's a 64-bit hash, because it's important for the keys to be
 * unique.
 */
static inline u64 iterate_chain_key(u64 key, u32 idx)
{
	u32 k0 = key, k1 = key >> 32;

	__jhash_mix(idx, k0, k1); /* Macro that modifies arguments! */

	return k0 | (u64)k1 << 32;
}

void lockdep_off(void)
{
	current->lockdep_recursion++;
}
EXPORT_SYMBOL(lockdep_off);

void lockdep_on(void)
{
	current->lockdep_recursion--;
}
EXPORT_SYMBOL(lockdep_on);

/*
 * Debugging switches:
 */

#define VERBOSE			0
#define VERY_VERBOSE		0

#if VERBOSE
# define HARDIRQ_VERBOSE	1
# define SOFTIRQ_VERBOSE	1
# define RECLAIM_VERBOSE	1
#else
# define HARDIRQ_VERBOSE	0
# define SOFTIRQ_VERBOSE	0
# define RECLAIM_VERBOSE	0
#endif

#if VERBOSE || HARDIRQ_VERBOSE || SOFTIRQ_VERBOSE || RECLAIM_VERBOSE
/*
 * Quick filtering for interesting events:
 */
static int class_filter(struct lock_class *class)
{
#if 0
	/* Example */
	if (class->name_version == 1 &&
			!strcmp(class->name, "lockname"))
		return 1;
	if (class->name_version == 1 &&
			!strcmp(class->name, "&struct->lockfield"))
		return 1;
#endif
	/* Filter everything else. 1 would be to allow everything else */
	return 0;
}
#endif

static int verbose(struct lock_class *class)
{
#if VERBOSE
	return class_filter(class);
#endif
	return 0;
}

/*
 * Stack-trace: tightly packed array of stack backtrace
 * addresses. Protected by the graph_lock.
 */
unsigned long nr_stack_trace_entries;
static unsigned long stack_trace[MAX_STACK_TRACE_ENTRIES];

static void print_lockdep_off(const char *bug_msg)
{
	printk(KERN_DEBUG "%s\n", bug_msg);
	printk(KERN_DEBUG "turning off the locking correctness validator.\n");
#ifdef CONFIG_LOCK_STAT
	printk(KERN_DEBUG "Please attach the output of /proc/lock_stat to the bug report\n");
#endif
}

static int save_trace(struct stack_trace *trace)
{
	trace->nr_entries = 0;
	trace->max_entries = MAX_STACK_TRACE_ENTRIES - nr_stack_trace_entries;
	trace->entries = stack_trace + nr_stack_trace_entries;

	trace->skip = 3;

	save_stack_trace(trace);

	/*
	 * Some daft arches put -1 at the end to indicate its a full trace.
	 *
	 * <rant> this is buggy anyway, since it takes a whole extra entry so a
	 * complete trace that maxes out the entries provided will be reported
	 * as incomplete, friggin useless </rant>
	 */
	if (trace->nr_entries != 0 &&
	    trace->entries[trace->nr_entries-1] == ULONG_MAX)
		trace->nr_entries--;

	trace->max_entries = trace->nr_entries;

	nr_stack_trace_entries += trace->nr_entries;

	if (nr_stack_trace_entries >= MAX_STACK_TRACE_ENTRIES-1) {
		if (!debug_locks_off_graph_unlock())
			return 0;

		print_lockdep_off("BUG: MAX_STACK_TRACE_ENTRIES too low!");
		dump_stack();

		return 0;
	}

	return 1;
}

unsigned int nr_hardirq_chains;
unsigned int nr_softirq_chains;
unsigned int nr_process_chains;
unsigned int max_lockdep_depth;

#ifdef CONFIG_DEBUG_LOCKDEP
/*
 * Various lockdep statistics:
 */
DEFINE_PER_CPU(struct lockdep_stats, lockdep_stats);
#endif

/*
 * Locking printouts:
 */

#define __USAGE(__STATE)						\
	[LOCK_USED_IN_##__STATE] = "IN-"__stringify(__STATE)"-W",	\
	[LOCK_ENABLED_##__STATE] = __stringify(__STATE)"-ON-W",		\
	[LOCK_USED_IN_##__STATE##_READ] = "IN-"__stringify(__STATE)"-R",\
	[LOCK_ENABLED_##__STATE##_READ] = __stringify(__STATE)"-ON-R",

static const char *usage_str[] =
{
#define LOCKDEP_STATE(__STATE) __USAGE(__STATE)
#include "lockdep_states.h"
#undef LOCKDEP_STATE
	[LOCK_USED] = "INITIAL USE",
};

const char * __get_key_name(struct lockdep_subclass_key *key, char *str)
{
	return kallsyms_lookup((unsigned long)key, NULL, NULL, NULL, str);
}

static inline unsigned long lock_flag(enum lock_usage_bit bit)
{
	return 1UL << bit;
}

static char get_usage_char(struct lock_class *class, enum lock_usage_bit bit)
{
	char c = '.';

	if (class->usage_mask & lock_flag(bit + 2))
		c = '+';
	if (class->usage_mask & lock_flag(bit)) {
		c = '-';
		if (class->usage_mask & lock_flag(bit + 2))
			c = '?';
	}

	return c;
}

void get_usage_chars(struct lock_class *class, char usage[LOCK_USAGE_CHARS])
{
	int i = 0;

#define LOCKDEP_STATE(__STATE) 						\
	usage[i++] = get_usage_char(class, LOCK_USED_IN_##__STATE);	\
	usage[i++] = get_usage_char(class, LOCK_USED_IN_##__STATE##_READ);
#include "lockdep_states.h"
#undef LOCKDEP_STATE

	usage[i] = '\0';
}

static void __print_lock_name(struct lock_class *class)
{
	char str[KSYM_NAME_LEN];
	const char *name;

	name = class->name;
	if (!name) {
		name = __get_key_name(class->key, str);
		printk(KERN_CONT "%s", name);
	} else {
		printk(KERN_CONT "%s", name);
		if (class->name_version > 1)
			printk(KERN_CONT "#%d", class->name_version);
		if (class->subclass)
			printk(KERN_CONT "/%d", class->subclass);
	}
}

static void print_lock_name(struct lock_class *class)
{
	char usage[LOCK_USAGE_CHARS];

	get_usage_chars(class, usage);

	printk(KERN_CONT " (");
	__print_lock_name(class);
	printk(KERN_CONT "){%s}", usage);
}

static void print_lockdep_cache(struct lockdep_map *lock)
{
	const char *name;
	char str[KSYM_NAME_LEN];

	name = lock->name;
	if (!name)
		name = __get_key_name(lock->key->subkeys, str);

	printk(KERN_CONT "%s", name);
}

static void print_lock(struct held_lock *hlock)
{
	/*
	 * We can be called locklessly through debug_show_all_locks() so be
	 * extra careful, the hlock might have been released and cleared.
	 */
	unsigned int class_idx = hlock->class_idx;

	/* Don't re-read hlock->class_idx, can't use READ_ONCE() on bitfields: */
	barrier();

	if (!class_idx || (class_idx - 1) >= MAX_LOCKDEP_KEYS) {
		printk(KERN_CONT "<RELEASED>\n");
		return;
	}

	print_lock_name(lock_classes + class_idx - 1);
	printk(KERN_CONT ", at: [<%p>] %pS\n",
		(void *)hlock->acquire_ip, (void *)hlock->acquire_ip);
}

static void lockdep_print_held_locks(struct task_struct *curr)
{
	int i, depth = curr->lockdep_depth;

	if (!depth) {
		printk("no locks held by %s/%d.\n", curr->comm, task_pid_nr(curr));
		return;
	}
	printk("%d lock%s held by %s/%d:\n",
		depth, depth > 1 ? "s" : "", curr->comm, task_pid_nr(curr));

	for (i = 0; i < depth; i++) {
		printk(" #%d: ", i);
		print_lock(curr->held_locks + i);
	}
}

static void print_kernel_ident(void)
{
	printk("%s %.*s %s\n", init_utsname()->release,
		(int)strcspn(init_utsname()->version, " "),
		init_utsname()->version,
		print_tainted());
}

static int very_verbose(struct lock_class *class)
{
#if VERY_VERBOSE
	return class_filter(class);
#endif
	return 0;
}

/*
 * Is this the address of a static object:
 */
#ifdef __KERNEL__
static int static_obj(void *obj)
{
	unsigned long start = (unsigned long) &_stext,
		      end   = (unsigned long) &_end,
		      addr  = (unsigned long) obj;

	/*
	 * static variable?
	 */
	if ((addr >= start) && (addr < end))
		return 1;

	if (arch_is_kernel_data(addr))
		return 1;

	/*
	 * in-kernel percpu var?
	 */
	if (is_kernel_percpu_address(addr))
		return 1;

	/*
	 * module static or percpu var?
	 */
	return is_module_address(addr) || is_module_percpu_address(addr);
}
#endif

/*
 * To make lock name printouts unique, we calculate a unique
 * class->name_version generation counter:
 */
static int count_matching_names(struct lock_class *new_class)
{
	struct lock_class *class;
	int count = 0;

	if (!new_class->name)
		return 0;

	list_for_each_entry_rcu(class, &all_lock_classes, lock_entry) {
		if (new_class->key - new_class->subclass == class->key)
			return class->name_version;
		if (class->name && !strcmp(class->name, new_class->name))
			count = max(count, class->name_version);
	}

	return count + 1;
}

/*
 * Register a lock's class in the hash-table, if the class is not present
 * yet. Otherwise we look it up. We cache the result in the lock object
 * itself, so actual lookup of the hash should be once per lock object.
 */
static inline struct lock_class *
look_up_lock_class(struct lockdep_map *lock, unsigned int subclass)
{
	struct lockdep_subclass_key *key;
	struct hlist_head *hash_head;
	struct lock_class *class;
	bool is_static = false;

	if (unlikely(subclass >= MAX_LOCKDEP_SUBCLASSES)) {
		debug_locks_off();
		printk(KERN_ERR
			"BUG: looking up invalid subclass: %u\n", subclass);
		printk(KERN_ERR
			"turning off the locking correctness validator.\n");
		dump_stack();
		return NULL;
	}

	/*
	 * Static locks do not have their class-keys yet - for them the key
	 * is the lock object itself. If the lock is in the per cpu area,
	 * the canonical address of the lock (per cpu offset removed) is
	 * used.
	 */
	if (unlikely(!lock->key)) {
		unsigned long can_addr, addr = (unsigned long)lock;

		if (__is_kernel_percpu_address(addr, &can_addr))
			lock->key = (void *)can_addr;
		else if (__is_module_percpu_address(addr, &can_addr))
			lock->key = (void *)can_addr;
		else if (static_obj(lock))
			lock->key = (void *)lock;
		else
			return ERR_PTR(-EINVAL);
		is_static = true;
	}

	/*
	 * NOTE: the class-key must be unique. For dynamic locks, a static
	 * lock_class_key variable is passed in through the mutex_init()
	 * (or spin_lock_init()) call - which acts as the key. For static
	 * locks we use the lock object itself as the key.
	 */
	BUILD_BUG_ON(sizeof(struct lock_class_key) >
			sizeof(struct lockdep_map));

	key = lock->key->subkeys + subclass;

	hash_head = classhashentry(key);

	/*
	 * We do an RCU walk of the hash, see lockdep_free_key_range().
	 */
	if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
		return NULL;

	hlist_for_each_entry_rcu(class, hash_head, hash_entry) {
		if (class->key == key) {
			/*
			 * Huh! same key, different name? Did someone trample
			 * on some memory? We're most confused.
			 */
			WARN_ON_ONCE(class->name != lock->name);
			return class;
		}
	}

	return is_static || static_obj(lock->key) ? NULL : ERR_PTR(-EINVAL);
}

/*
 * Register a lock's class in the hash-table, if the class is not present
 * yet. Otherwise we look it up. We cache the result in the lock object
 * itself, so actual lookup of the hash should be once per lock object.
 */
static struct lock_class *
register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force)
{
	struct lockdep_subclass_key *key;
	struct hlist_head *hash_head;
	struct lock_class *class;

	DEBUG_LOCKS_WARN_ON(!irqs_disabled());

	class = look_up_lock_class(lock, subclass);
	if (likely(!IS_ERR_OR_NULL(class)))
		goto out_set_class_cache;

	/*
	 * Debug-check: all keys must be persistent!
	 */
	if (IS_ERR(class)) {
		debug_locks_off();
		printk("INFO: trying to register non-static key.\n");
		printk("the code is fine but needs lockdep annotation.\n");
		printk("turning off the locking correctness validator.\n");
		dump_stack();
		return NULL;
	}

	key = lock->key->subkeys + subclass;
	hash_head = classhashentry(key);

	if (!graph_lock()) {
		return NULL;
	}
	/*
	 * We have to do the hash-walk again, to avoid races
	 * with another CPU:
	 */
	hlist_for_each_entry_rcu(class, hash_head, hash_entry) {
		if (class->key == key)
			goto out_unlock_set;
	}

	/*
	 * Allocate a new key from the static array, and add it to
	 * the hash:
	 */
	if (nr_lock_classes >= MAX_LOCKDEP_KEYS) {
		if (!debug_locks_off_graph_unlock()) {
			return NULL;
		}

		print_lockdep_off("BUG: MAX_LOCKDEP_KEYS too low!");
		dump_stack();
		return NULL;
	}
	class = lock_classes + nr_lock_classes++;
	debug_atomic_inc(nr_unused_locks);
	class->key = key;
	class->name = lock->name;
	class->subclass = subclass;
	INIT_LIST_HEAD(&class->lock_entry);
	INIT_LIST_HEAD(&class->locks_before);
	INIT_LIST_HEAD(&class->locks_after);
	class->name_version = count_matching_names(class);
	/*
	 * We use RCU's safe list-add method to make
	 * parallel walking of the hash-list safe:
	 */
	hlist_add_head_rcu(&class->hash_entry, hash_head);
	/*
	 * Add it to the global list of classes:
	 */
	list_add_tail_rcu(&class->lock_entry, &all_lock_classes);

	if (verbose(class)) {
		graph_unlock();

		printk("\nnew class %p: %s", class->key, class->name);
		if (class->name_version > 1)
			printk(KERN_CONT "#%d", class->name_version);
		printk(KERN_CONT "\n");
		dump_stack();

		if (!graph_lock()) {
			return NULL;
		}
	}
out_unlock_set:
	graph_unlock();

out_set_class_cache:
	if (!subclass || force)
		lock->class_cache[0] = class;
	else if (subclass < NR_LOCKDEP_CACHING_CLASSES)
		lock->class_cache[subclass] = class;

	/*
	 * Hash collision, did we smoke some? We found a class with a matching
	 * hash but the subclass -- which is hashed in -- didn't match.
	 */
	if (DEBUG_LOCKS_WARN_ON(class->subclass != subclass))
		return NULL;

	return class;
}

#ifdef CONFIG_PROVE_LOCKING
/*
 * Allocate a lockdep entry. (assumes the graph_lock held, returns
 * with NULL on failure)
 */
static struct lock_list *alloc_list_entry(void)
{
	if (nr_list_entries >= MAX_LOCKDEP_ENTRIES) {
		if (!debug_locks_off_graph_unlock())
			return NULL;

		print_lockdep_off("BUG: MAX_LOCKDEP_ENTRIES too low!");
		dump_stack();
		return NULL;
	}
	return list_entries + nr_list_entries++;
}

/*
 * Add a new dependency to the head of the list:
 */
static int add_lock_to_list(struct lock_class *this, struct list_head *head,
			    unsigned long ip, int distance,
			    struct stack_trace *trace)
{
	struct lock_list *entry;
	/*
	 * Lock not present yet - get a new dependency struct and
	 * add it to the list:
	 */
	entry = alloc_list_entry();
	if (!entry)
		return 0;

	entry->class = this;
	entry->distance = distance;
	entry->trace = *trace;
	/*
	 * Both allocation and removal are done under the graph lock; but
	 * iteration is under RCU-sched; see look_up_lock_class() and
	 * lockdep_free_key_range().
	 */
	list_add_tail_rcu(&entry->entry, head);

	return 1;
}

/*
 * For good efficiency of modular, we use power of 2
 */
#define MAX_CIRCULAR_QUEUE_SIZE		4096UL
#define CQ_MASK				(MAX_CIRCULAR_QUEUE_SIZE-1)

/*
 * The circular_queue and helpers is used to implement the
 * breadth-first search(BFS)algorithem, by which we can build
 * the shortest path from the next lock to be acquired to the
 * previous held lock if there is a circular between them.
 */
struct circular_queue {
	unsigned long element[MAX_CIRCULAR_QUEUE_SIZE];
	unsigned int  front, rear;
};

static struct circular_queue lock_cq;

unsigned int max_bfs_queue_depth;

static unsigned int lockdep_dependency_gen_id;

static inline void __cq_init(struct circular_queue *cq)
{
	cq->front = cq->rear = 0;
	lockdep_dependency_gen_id++;
}

static inline int __cq_empty(struct circular_queue *cq)
{
	return (cq->front == cq->rear);
}

static inline int __cq_full(struct circular_queue *cq)
{
	return ((cq->rear + 1) & CQ_MASK) == cq->front;
}

static inline int __cq_enqueue(struct circular_queue *cq, unsigned long elem)
{
	if (__cq_full(cq))
		return -1;

	cq->element[cq->rear] = elem;
	cq->rear = (cq->rear + 1) & CQ_MASK;
	return 0;
}

static inline int __cq_dequeue(struct circular_queue *cq, unsigned long *elem)
{
	if (__cq_empty(cq))
		return -1;

	*elem = cq->element[cq->front];
	cq->front = (cq->front + 1) & CQ_MASK;
	return 0;
}

static inline unsigned int  __cq_get_elem_count(struct circular_queue *cq)
{
	return (cq->rear - cq->front) & CQ_MASK;
}

static inline void mark_lock_accessed(struct lock_list *lock,
					struct lock_list *parent)
{
	unsigned long nr;

	nr = lock - list_entries;
	WARN_ON(nr >= nr_list_entries); /* Out-of-bounds, input fail */
	lock->parent = parent;
	lock->class->dep_gen_id = lockdep_dependency_gen_id;
}

static inline unsigned long lock_accessed(struct lock_list *lock)
{
	unsigned long nr;

	nr = lock - list_entries;
	WARN_ON(nr >= nr_list_entries); /* Out-of-bounds, input fail */
	return lock->class->dep_gen_id == lockdep_dependency_gen_id;
}

static inline struct lock_list *get_lock_parent(struct lock_list *child)
{
	return child->parent;
}

static inline int get_lock_depth(struct lock_list *child)
{
	int depth = 0;
	struct lock_list *parent;

	while ((parent = get_lock_parent(child))) {
		child = parent;
		depth++;
	}
	return depth;
}

static int __bfs(struct lock_list *source_entry,
		 void *data,
		 int (*match)(struct lock_list *entry, void *data),
		 struct lock_list **target_entry,
		 int forward)
{
	struct lock_list *entry;
	struct list_head *head;
	struct circular_queue *cq = &lock_cq;
	int ret = 1;

	if (match(source_entry, data)) {
		*target_entry = source_entry;
		ret = 0;
		goto exit;
	}

	if (forward)
		head = &source_entry->class->locks_after;
	else
		head = &source_entry->class->locks_before;

	if (list_empty(head))
		goto exit;

	__cq_init(cq);
	__cq_enqueue(cq, (unsigned long)source_entry);

	while (!__cq_empty(cq)) {
		struct lock_list *lock;

		__cq_dequeue(cq, (unsigned long *)&lock);

		if (!lock->class) {
			ret = -2;
			goto exit;
		}

		if (forward)
			head = &lock->class->locks_after;
		else
			head = &lock->class->locks_before;

		DEBUG_LOCKS_WARN_ON(!irqs_disabled());

		list_for_each_entry_rcu(entry, head, entry) {
			if (!lock_accessed(entry)) {
				unsigned int cq_depth;
				mark_lock_accessed(entry, lock);
				if (match(entry, data)) {
					*target_entry = entry;
					ret = 0;
					goto exit;
				}

				if (__cq_enqueue(cq, (unsigned long)entry)) {
					ret = -1;
					goto exit;
				}
				cq_depth = __cq_get_elem_count(cq);
				if (max_bfs_queue_depth < cq_depth)
					max_bfs_queue_depth = cq_depth;
			}
		}
	}
exit:
	return ret;
}

static inline int __bfs_forwards(struct lock_list *src_entry,
			void *data,
			int (*match)(struct lock_list *entry, void *data),
			struct lock_list **target_entry)
{
	return __bfs(src_entry, data, match, target_entry, 1);

}

static inline int __bfs_backwards(struct lock_list *src_entry,
			void *data,
			int (*match)(struct lock_list *entry, void *data),
			struct lock_list **target_entry)
{
	return __bfs(src_entry, data, match, target_entry, 0);

}

/*
 * Recursive, forwards-direction lock-dependency checking, used for
 * both noncyclic checking and for hardirq-unsafe/softirq-unsafe
 * checking.
 */

/*
 * Print a dependency chain entry (this is only done when a deadlock
 * has been detected):
 */
static noinline int
print_circular_bug_entry(struct lock_list *target, int depth)
{
	if (debug_locks_silent)
		return 0;
	printk("\n-> #%u", depth);
	print_lock_name(target->class);
	printk(KERN_CONT ":\n");
	print_stack_trace(&target->trace, 6);

	return 0;
}

static void
print_circular_lock_scenario(struct held_lock *src,
			     struct held_lock *tgt,
			     struct lock_list *prt)
{
	struct lock_class *source = hlock_class(src);
	struct lock_class *target = hlock_class(tgt);
	struct lock_class *parent = prt->class;

	/*
	 * A direct locking problem where unsafe_class lock is taken
	 * directly by safe_class lock, then all we need to show
	 * is the deadlock scenario, as it is obvious that the
	 * unsafe lock is taken under the safe lock.
	 *
	 * But if there is a chain instead, where the safe lock takes
	 * an intermediate lock (middle_class) where this lock is
	 * not the same as the safe lock, then the lock chain is
	 * used to describe the problem. Otherwise we would need
	 * to show a different CPU case for each link in the chain
	 * from the safe_class lock to the unsafe_class lock.
	 */
	if (parent != source) {
		printk("Chain exists of:\n  ");
		__print_lock_name(source);
		printk(KERN_CONT " --> ");
		__print_lock_name(parent);
		printk(KERN_CONT " --> ");
		__print_lock_name(target);
		printk(KERN_CONT "\n\n");
	}

	printk(" Possible unsafe locking scenario:\n\n");
	printk("       CPU0                    CPU1\n");
	printk("       ----                    ----\n");
	printk("  lock(");
	__print_lock_name(target);
	printk(KERN_CONT ");\n");
	printk("                               lock(");
	__print_lock_name(parent);
	printk(KERN_CONT ");\n");
	printk("                               lock(");
	__print_lock_name(target);
	printk(KERN_CONT ");\n");
	printk("  lock(");
	__print_lock_name(source);
	printk(KERN_CONT ");\n");
	printk("\n *** DEADLOCK ***\n\n");
}

/*
 * When a circular dependency is detected, print the
 * header first:
 */
static noinline int
print_circular_bug_header(struct lock_list *entry, unsigned int depth,
			struct held_lock *check_src,
			struct held_lock *check_tgt)
{
	struct task_struct *curr = current;

	if (debug_locks_silent)
		return 0;

	printk("\n");
	pr_warn("======================================================\n");
	pr_warn("WARNING: possible circular locking dependency detected\n");
	print_kernel_ident();
	pr_warn("------------------------------------------------------\n");
	printk("%s/%d is trying to acquire lock:\n",
		curr->comm, task_pid_nr(curr));
	print_lock(check_src);
	printk("\nbut task is already holding lock:\n");
	print_lock(check_tgt);
	printk("\nwhich lock already depends on the new lock.\n\n");
	printk("\nthe existing dependency chain (in reverse order) is:\n");

	print_circular_bug_entry(entry, depth);

	return 0;
}

static inline int class_equal(struct lock_list *entry, void *data)
{
	return entry->class == data;
}

static noinline int print_circular_bug(struct lock_list *this,
				struct lock_list *target,
				struct held_lock *check_src,
				struct held_lock *check_tgt)
{
	struct task_struct *curr = current;
	struct lock_list *parent;
	struct lock_list *first_parent;
	int depth;

	if (!debug_locks_off_graph_unlock() || debug_locks_silent)
		return 0;

	if (!save_trace(&this->trace))
		return 0;

	depth = get_lock_depth(target);

	print_circular_bug_header(target, depth, check_src, check_tgt);

	parent = get_lock_parent(target);
	first_parent = parent;

	while (parent) {
		print_circular_bug_entry(parent, --depth);
		parent = get_lock_parent(parent);
	}

	printk("\nother info that might help us debug this:\n\n");
	print_circular_lock_scenario(check_src, check_tgt,
				     first_parent);

	lockdep_print_held_locks(curr);

	printk("\nstack backtrace:\n");
	dump_stack();

	return 0;
}

static noinline int print_bfs_bug(int ret)
{
	if (!debug_locks_off_graph_unlock())
		return 0;

	/*
	 * Breadth-first-search failed, graph got corrupted?
	 */
	WARN(1, "lockdep bfs error:%d\n", ret);

	return 0;
}

static int noop_count(struct lock_list *entry, void *data)
{
	(*(unsigned long *)data)++;
	return 0;
}

static unsigned long __lockdep_count_forward_deps(struct lock_list *this)
{
	unsigned long  count = 0;
	struct lock_list *uninitialized_var(target_entry);

	__bfs_forwards(this, (void *)&count, noop_count, &target_entry);

	return count;
}
unsigned long lockdep_count_forward_deps(struct lock_class *class)
{
	unsigned long ret, flags;
	struct lock_list this;

	this.parent = NULL;
	this.class = class;

	local_irq_save(flags);
	arch_spin_lock(&lockdep_lock);
	ret = __lockdep_count_forward_deps(&this);
	arch_spin_unlock(&lockdep_lock);
	local_irq_restore(flags);

	return ret;
}

static unsigned long __lockdep_count_backward_deps(struct lock_list *this)
{
	unsigned long  count = 0;
	struct lock_list *uninitialized_var(target_entry);

	__bfs_backwards(this, (void *)&count, noop_count, &target_entry);

	return count;
}

unsigned long lockdep_count_backward_deps(struct lock_class *class)
{
	unsigned long ret, flags;
	struct lock_list this;

	this.parent = NULL;
	this.class = class;

	local_irq_save(flags);
	arch_spin_lock(&lockdep_lock);
	ret = __lockdep_count_backward_deps(&this);
	arch_spin_unlock(&lockdep_lock);
	local_irq_restore(flags);

	return ret;
}

/*
 * Prove that the dependency graph starting at <entry> can not
 * lead to <target>. Print an error and return 0 if it does.
 */
static noinline int
check_noncircular(struct lock_list *root, struct lock_class *target,
		struct lock_list **target_entry)
{
	int result;

	debug_atomic_inc(nr_cyclic_checks);

	result = __bfs_forwards(root, target, class_equal, target_entry);

	return result;
}

#if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING)
/*
 * Forwards and backwards subgraph searching, for the purposes of
 * proving that two subgraphs can be connected by a new dependency
 * without creating any illegal irq-safe -> irq-unsafe lock dependency.
 */

static inline int usage_match(struct lock_list *entry, void *bit)
{
	return entry->class->usage_mask & (1 << (enum lock_usage_bit)bit);
}



/*
 * Find a node in the forwards-direction dependency sub-graph starting
 * at @root->class that matches @bit.
 *
 * Return 0 if such a node exists in the subgraph, and put that node
 * into *@target_entry.
 *
 * Return 1 otherwise and keep *@target_entry unchanged.
 * Return <0 on error.
 */
static int
find_usage_forwards(struct lock_list *root, enum lock_usage_bit bit,
			struct lock_list **target_entry)
{
	int result;

	debug_atomic_inc(nr_find_usage_forwards_checks);

	result = __bfs_forwards(root, (void *)bit, usage_match, target_entry);

	return result;
}

/*
 * Find a node in the backwards-direction dependency sub-graph starting
 * at @root->class that matches @bit.
 *
 * Return 0 if such a node exists in the subgraph, and put that node
 * into *@target_entry.
 *
 * Return 1 otherwise and keep *@target_entry unchanged.
 * Return <0 on error.
 */
static int
find_usage_backwards(struct lock_list *root, enum lock_usage_bit bit,
			struct lock_list **target_entry)
{
	int result;

	debug_atomic_inc(nr_find_usage_backwards_checks);

	result = __bfs_backwards(root, (void *)bit, usage_match, target_entry);

	return result;
}

static void print_lock_class_header(struct lock_class *class, int depth)
{
	int bit;

	printk("%*s->", depth, "");
	print_lock_name(class);
	printk(KERN_CONT " ops: %lu", class->ops);
	printk(KERN_CONT " {\n");

	for (bit = 0; bit < LOCK_USAGE_STATES; bit++) {
		if (class->usage_mask & (1 << bit)) {
			int len = depth;

			len += printk("%*s   %s", depth, "", usage_str[bit]);
			len += printk(KERN_CONT " at:\n");
			print_stack_trace(class->usage_traces + bit, len);
		}
	}
	printk("%*s }\n", depth, "");

	printk("%*s ... key      at: [<%p>] %pS\n",
		depth, "", class->key, class->key);
}

/*
 * printk the shortest lock dependencies from @start to @end in reverse order:
 */
static void __used
print_shortest_lock_dependencies(struct lock_list *leaf,
				struct lock_list *root)
{
	struct lock_list *entry = leaf;
	int depth;

	/*compute depth from generated tree by BFS*/
	depth = get_lock_depth(leaf);

	do {
		print_lock_class_header(entry->class, depth);
		printk("%*s ... acquired at:\n", depth, "");
		print_stack_trace(&entry->trace, 2);
		printk("\n");

		if (depth == 0 && (entry != root)) {
			printk("lockdep:%s bad path found in chain graph\n", __func__);
			break;
		}

		entry = get_lock_parent(entry);
		depth--;
	} while (entry && (depth >= 0));

	return;
}

static void
print_irq_lock_scenario(struct lock_list *safe_entry,
			struct lock_list *unsafe_entry,
			struct lock_class *prev_class,
			struct lock_class *next_class)
{
	struct lock_class *safe_class = safe_entry->class;
	struct lock_class *unsafe_class = unsafe_entry->class;
	struct lock_class *middle_class = prev_class;

	if (middle_class == safe_class)
		middle_class = next_class;

	/*
	 * A direct locking problem where unsafe_class lock is taken
	 * directly by safe_class lock, then all we need to show
	 * is the deadlock scenario, as it is obvious that the
	 * unsafe lock is taken under the safe lock.
	 *
	 * But if there is a chain instead, where the safe lock takes
	 * an intermediate lock (middle_class) where this lock is
	 * not the same as the safe lock, then the lock chain is
	 * used to describe the problem. Otherwise we would need
	 * to show a different CPU case for each link in the chain
	 * from the safe_class lock to the unsafe_class lock.
	 */
	if (middle_class != unsafe_class) {
		printk("Chain exists of:\n  ");
		__print_lock_name(safe_class);
		printk(KERN_CONT " --> ");
		__print_lock_name(middle_class);
		printk(KERN_CONT " --> ");
		__print_lock_name(unsafe_class);
		printk(KERN_CONT "\n\n");
	}

	printk(" Possible interrupt unsafe locking scenario:\n\n");
	printk("       CPU0                    CPU1\n");
	printk("       ----                    ----\n");
	printk("  lock(");
	__print_lock_name(unsafe_class);
	printk(KERN_CONT ");\n");
	printk("                               local_irq_disable();\n");
	printk("                               lock(");
	__print_lock_name(safe_class);
	printk(KERN_CONT ");\n");
	printk("                               lock(");
	__print_lock_name(middle_class);
	printk(KERN_CONT ");\n");
	printk("  <Interrupt>\n");
	printk("    lock(");
	__print_lock_name(safe_class);
	printk(KERN_CONT ");\n");
	printk("\n *** DEADLOCK ***\n\n");
}

static int
print_bad_irq_dependency(struct task_struct *curr,
			 struct lock_list *prev_root,
			 struct lock_list *next_root,
			 struct lock_list *backwards_entry,
			 struct lock_list *forwards_entry,
			 struct held_lock *prev,
			 struct held_lock *next,
			 enum lock_usage_bit bit1,
			 enum lock_usage_bit bit2,
			 const char *irqclass)
{
	if (!debug_locks_off_graph_unlock() || debug_locks_silent)
		return 0;

	printk("\n");
	pr_warn("=====================================================\n");
	pr_warn("WARNING: %s-safe -> %s-unsafe lock order detected\n",
		irqclass, irqclass);
	print_kernel_ident();
	pr_warn("-----------------------------------------------------\n");
	printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] is trying to acquire:\n",
		curr->comm, task_pid_nr(curr),
		curr->hardirq_context, hardirq_count() >> HARDIRQ_SHIFT,
		curr->softirq_context, softirq_count() >> SOFTIRQ_SHIFT,
		curr->hardirqs_enabled,
		curr->softirqs_enabled);
	print_lock(next);

	printk("\nand this task is already holding:\n");
	print_lock(prev);
	printk("which would create a new lock dependency:\n");
	print_lock_name(hlock_class(prev));
	printk(KERN_CONT " ->");
	print_lock_name(hlock_class(next));
	printk(KERN_CONT "\n");

	printk("\nbut this new dependency connects a %s-irq-safe lock:\n",
		irqclass);
	print_lock_name(backwards_entry->class);
	printk("\n... which became %s-irq-safe at:\n", irqclass);

	print_stack_trace(backwards_entry->class->usage_traces + bit1, 1);

	printk("\nto a %s-irq-unsafe lock:\n", irqclass);
	print_lock_name(forwards_entry->class);
	printk("\n... which became %s-irq-unsafe at:\n", irqclass);
	printk("...");

	print_stack_trace(forwards_entry->class->usage_traces + bit2, 1);

	printk("\nother info that might help us debug this:\n\n");
	print_irq_lock_scenario(backwards_entry, forwards_entry,
				hlock_class(prev), hlock_class(next));

	lockdep_print_held_locks(curr);

	printk("\nthe dependencies between %s-irq-safe lock and the holding lock:\n", irqclass);
	if (!save_trace(&prev_root->trace))
		return 0;
	print_shortest_lock_dependencies(backwards_entry, prev_root);

	printk("\nthe dependencies between the lock to be acquired");
	printk(" and %s-irq-unsafe lock:\n", irqclass);
	if (!save_trace(&next_root->trace))
		return 0;
	print_shortest_lock_dependencies(forwards_entry, next_root);

	printk("\nstack backtrace:\n");
	dump_stack();

	return 0;
}

static int
check_usage(struct task_struct *curr, struct held_lock *prev,
	    struct held_lock *next, enum lock_usage_bit bit_backwards,
	    enum lock_usage_bit bit_forwards, const char *irqclass)
{
	int ret;
	struct lock_list this, that;
	struct lock_list *uninitialized_var(target_entry);
	struct lock_list *uninitialized_var(target_entry1);

	this.parent = NULL;

	this.class = hlock_class(prev);
	ret = find_usage_backwards(&this, bit_backwards, &target_entry);
	if (ret < 0)
		return print_bfs_bug(ret);
	if (ret == 1)
		return ret;

	that.parent = NULL;
	that.class = hlock_class(next);
	ret = find_usage_forwards(&that, bit_forwards, &target_entry1);
	if (ret < 0)
		return print_bfs_bug(ret);
	if (ret == 1)
		return ret;

	return print_bad_irq_dependency(curr, &this, &that,
			target_entry, target_entry1,
			prev, next,
			bit_backwards, bit_forwards, irqclass);
}

static const char *state_names[] = {
#define LOCKDEP_STATE(__STATE) \
	__stringify(__STATE),
#include "lockdep_states.h"
#undef LOCKDEP_STATE
};

static const char *state_rnames[] = {
#define LOCKDEP_STATE(__STATE) \
	__stringify(__STATE)"-READ",
#include "lockdep_states.h"
#undef LOCKDEP_STATE
};

static inline const char *state_name(enum lock_usage_bit bit)
{
	return (bit & 1) ? state_rnames[bit >> 2] : state_names[bit >> 2];
}

static int exclusive_bit(int new_bit)
{
	/*
	 * USED_IN
	 * USED_IN_READ
	 * ENABLED
	 * ENABLED_READ
	 *
	 * bit 0 - write/read
	 * bit 1 - used_in/enabled
	 * bit 2+  state
	 */

	int state = new_bit & ~3;
	int dir = new_bit & 2;

	/*
	 * keep state, bit flip the direction and strip read.
	 */
	return state | (dir ^ 2);
}

static int check_irq_usage(struct task_struct *curr, struct held_lock *prev,
			   struct held_lock *next, enum lock_usage_bit bit)
{
	/*
	 * Prove that the new dependency does not connect a hardirq-safe
	 * lock with a hardirq-unsafe lock - to achieve this we search
	 * the backwards-subgraph starting at <prev>, and the
	 * forwards-subgraph starting at <next>:
	 */
	if (!check_usage(curr, prev, next, bit,
			   exclusive_bit(bit), state_name(bit)))
		return 0;

	bit++; /* _READ */

	/*
	 * Prove that the new dependency does not connect a hardirq-safe-read
	 * lock with a hardirq-unsafe lock - to achieve this we search
	 * the backwards-subgraph starting at <prev>, and the
	 * forwards-subgraph starting at <next>:
	 */
	if (!check_usage(curr, prev, next, bit,
			   exclusive_bit(bit), state_name(bit)))
		return 0;

	return 1;
}

static int
check_prev_add_irq(struct task_struct *curr, struct held_lock *prev,
		struct held_lock *next)
{
#define LOCKDEP_STATE(__STATE)						\
	if (!check_irq_usage(curr, prev, next, LOCK_USED_IN_##__STATE))	\
		return 0;
#include "lockdep_states.h"
#undef LOCKDEP_STATE

	return 1;
}

static void inc_chains(void)
{
	if (current->hardirq_context)
		nr_hardirq_chains++;
	else {
		if (current->softirq_context)
			nr_softirq_chains++;
		else
			nr_process_chains++;
	}
}

#else

static inline int
check_prev_add_irq(struct task_struct *curr, struct held_lock *prev,
		struct held_lock *next)
{
	return 1;
}

static inline void inc_chains(void)
{
	nr_process_chains++;
}

#endif

static void
print_deadlock_scenario(struct held_lock *nxt,
			     struct held_lock *prv)
{
	struct lock_class *next = hlock_class(nxt);
	struct lock_class *prev = hlock_class(prv);

	printk(" Possible unsafe locking scenario:\n\n");
	printk("       CPU0\n");
	printk("       ----\n");
	printk("  lock(");
	__print_lock_name(prev);
	printk(KERN_CONT ");\n");
	printk("  lock(");
	__print_lock_name(next);
	printk(KERN_CONT ");\n");
	printk("\n *** DEADLOCK ***\n\n");
	printk(" May be due to missing lock nesting notation\n\n");
}

static int
print_deadlock_bug(struct task_struct *curr, struct held_lock *prev,
		   struct held_lock *next)
{
	if (!debug_locks_off_graph_unlock() || debug_locks_silent)
		return 0;

	printk("\n");
	pr_warn("============================================\n");
	pr_warn("WARNING: possible recursive locking detected\n");
	print_kernel_ident();
	pr_warn("--------------------------------------------\n");
	printk("%s/%d is trying to acquire lock:\n",
		curr->comm, task_pid_nr(curr));
	print_lock(next);
	printk("\nbut task is already holding lock:\n");
	print_lock(prev);

	printk("\nother info that might help us debug this:\n");
	print_deadlock_scenario(next, prev);
	lockdep_print_held_locks(curr);

	printk("\nstack backtrace:\n");
	dump_stack();

	return 0;
}

/*
 * Check whether we are holding such a class already.
 *
 * (Note that this has to be done separately, because the graph cannot
 * detect such classes of deadlocks.)
 *
 * Returns: 0 on deadlock detected, 1 on OK, 2 on recursive read
 */
static int
check_deadlock(struct task_struct *curr, struct held_lock *next,
	       struct lockdep_map *next_instance, int read)
{
	struct held_lock *prev;
	struct held_lock *nest = NULL;
	int i;

	for (i = 0; i < curr->lockdep_depth; i++) {
		prev = curr->held_locks + i;

		if (prev->instance == next->nest_lock)
			nest = prev;

		if (hlock_class(prev) != hlock_class(next))
			continue;

		/*
		 * Allow read-after-read recursion of the same
		 * lock class (i.e. read_lock(lock)+read_lock(lock)):
		 */
		if ((read == 2) && prev->read)
			return 2;

		/*
		 * We're holding the nest_lock, which serializes this lock's
		 * nesting behaviour.
		 */
		if (nest)
			return 2;

		return print_deadlock_bug(curr, prev, next);
	}
	return 1;
}

/*
 * There was a chain-cache miss, and we are about to add a new dependency
 * to a previous lock. We recursively validate the following rules:
 *
 *  - would the adding of the <prev> -> <next> dependency create a
 *    circular dependency in the graph? [== circular deadlock]
 *
 *  - does the new prev->next dependency connect any hardirq-safe lock
 *    (in the full backwards-subgraph starting at <prev>) with any
 *    hardirq-unsafe lock (in the full forwards-subgraph starting at
 *    <next>)? [== illegal lock inversion with hardirq contexts]
 *
 *  - does the new prev->next dependency connect any softirq-safe lock
 *    (in the full backwards-subgraph starting at <prev>) with any
 *    softirq-unsafe lock (in the full forwards-subgraph starting at
 *    <next>)? [== illegal lock inversion with softirq contexts]
 *
 * any of these scenarios could lead to a deadlock.
 *
 * Then if all the validations pass, we add the forwards and backwards
 * dependency.
 */
static int
check_prev_add(struct task_struct *curr, struct held_lock *prev,
	       struct held_lock *next, int distance, int *stack_saved)
{
	struct lock_list *entry;
	int ret;
	struct lock_list this;
	struct lock_list *uninitialized_var(target_entry);
	/*
	 * Static variable, serialized by the graph_lock().
	 *
	 * We use this static variable to save the stack trace in case
	 * we call into this function multiple times due to encountering
	 * trylocks in the held lock stack.
	 */
	static struct stack_trace trace;

	/*
	 * Prove that the new <prev> -> <next> dependency would not
	 * create a circular dependency in the graph. (We do this by
	 * forward-recursing into the graph starting at <next>, and
	 * checking whether we can reach <prev>.)
	 *
	 * We are using global variables to control the recursion, to
	 * keep the stackframe size of the recursive functions low:
	 */
	this.class = hlock_class(next);
	this.parent = NULL;
	ret = check_noncircular(&this, hlock_class(prev), &target_entry);
	if (unlikely(!ret))
		return print_circular_bug(&this, target_entry, next, prev);
	else if (unlikely(ret < 0))
		return print_bfs_bug(ret);

	if (!check_prev_add_irq(curr, prev, next))
		return 0;

	/*
	 * For recursive read-locks we do all the dependency checks,
	 * but we dont store read-triggered dependencies (only
	 * write-triggered dependencies). This ensures that only the
	 * write-side dependencies matter, and that if for example a
	 * write-lock never takes any other locks, then the reads are
	 * equivalent to a NOP.
	 */
	if (next->read == 2 || prev->read == 2)
		return 1;
	/*
	 * Is the <prev> -> <next> dependency already present?
	 *
	 * (this may occur even though this is a new chain: consider
	 *  e.g. the L1 -> L2 -> L3 -> L4 and the L5 -> L1 -> L2 -> L3
	 *  chains - the second one will be new, but L1 already has
	 *  L2 added to its dependency list, due to the first chain.)
	 */
	list_for_each_entry(entry, &hlock_class(prev)->locks_after, entry) {
		if (entry->class == hlock_class(next)) {
			if (distance == 1)
				entry->distance = 1;
			return 2;
		}
	}

	if (!*stack_saved) {
		if (!save_trace(&trace))
			return 0;
		*stack_saved = 1;
	}

	/*
	 * Ok, all validations passed, add the new lock
	 * to the previous lock's dependency list:
	 */
	ret = add_lock_to_list(hlock_class(next),
			       &hlock_class(prev)->locks_after,
			       next->acquire_ip, distance, &trace);

	if (!ret)
		return 0;

	ret = add_lock_to_list(hlock_class(prev),
			       &hlock_class(next)->locks_before,
			       next->acquire_ip, distance, &trace);
	if (!ret)
		return 0;

	/*
	 * Debugging printouts:
	 */
	if (verbose(hlock_class(prev)) || verbose(hlock_class(next))) {
		/* We drop graph lock, so another thread can overwrite trace. */
		*stack_saved = 0;
		graph_unlock();
		printk("\n new dependency: ");
		print_lock_name(hlock_class(prev));
		printk(KERN_CONT " => ");
		print_lock_name(hlock_class(next));
		printk(KERN_CONT "\n");
		dump_stack();
		return graph_lock();
	}
	return 1;
}

/*
 * Add the dependency to all directly-previous locks that are 'relevant'.
 * The ones that are relevant are (in increasing distance from curr):
 * all consecutive trylock entries and the final non-trylock entry - or
 * the end of this context's lock-chain - whichever comes first.
 */
static int
check_prevs_add(struct task_struct *curr, struct held_lock *next)
{
	int depth = curr->lockdep_depth;
	int stack_saved = 0;
	struct held_lock *hlock;

	/*
	 * Debugging checks.
	 *
	 * Depth must not be zero for a non-head lock:
	 */
	if (!depth)
		goto out_bug;
	/*
	 * At least two relevant locks must exist for this
	 * to be a head:
	 */
	if (curr->held_locks[depth].irq_context !=
			curr->held_locks[depth-1].irq_context)
		goto out_bug;

	for (;;) {
		int distance = curr->lockdep_depth - depth + 1;
		hlock = curr->held_locks + depth - 1;
		/*
		 * Only non-recursive-read entries get new dependencies
		 * added:
		 */
		if (hlock->read != 2 && hlock->check) {
			if (!check_prev_add(curr, hlock, next,
						distance, &stack_saved))
				return 0;
			/*
			 * Stop after the first non-trylock entry,
			 * as non-trylock entries have added their
			 * own direct dependencies already, so this
			 * lock is connected to them indirectly:
			 */
			if (!hlock->trylock)
				break;
		}
		depth--;
		/*
		 * End of lock-stack?
		 */
		if (!depth)
			break;
		/*
		 * Stop the search if we cross into another context:
		 */
		if (curr->held_locks[depth].irq_context !=
				curr->held_locks[depth-1].irq_context)
			break;
	}
	return 1;
out_bug:
	if (!debug_locks_off_graph_unlock())
		return 0;

	/*
	 * Clearly we all shouldn't be here, but since we made it we
	 * can reliable say we messed up our state. See the above two
	 * gotos for reasons why we could possibly end up here.
	 */
	WARN_ON(1);

	return 0;
}

unsigned long nr_lock_chains;
struct lock_chain lock_chains[MAX_LOCKDEP_CHAINS];
int nr_chain_hlocks;
static u16 chain_hlocks[MAX_LOCKDEP_CHAIN_HLOCKS];

struct lock_class *lock_chain_get_class(struct lock_chain *chain, int i)
{
	return lock_classes + chain_hlocks[chain->base + i];
}

/*
 * Returns the index of the first held_lock of the current chain
 */
static inline int get_first_held_lock(struct task_struct *curr,
					struct held_lock *hlock)
{
	int i;
	struct held_lock *hlock_curr;

	for (i = curr->lockdep_depth - 1; i >= 0; i--) {
		hlock_curr = curr->held_locks + i;
		if (hlock_curr->irq_context != hlock->irq_context)
			break;

	}

	return ++i;
}

#ifdef CONFIG_DEBUG_LOCKDEP
/*
 * Returns the next chain_key iteration
 */
static u64 print_chain_key_iteration(int class_idx, u64 chain_key)
{
	u64 new_chain_key = iterate_chain_key(chain_key, class_idx);

	printk(" class_idx:%d -> chain_key:%016Lx",
		class_idx,
		(unsigned long long)new_chain_key);
	return new_chain_key;
}

static void
print_chain_keys_held_locks(struct task_struct *curr, struct held_lock *hlock_next)
{
	struct held_lock *hlock;
	u64 chain_key = 0;
	int depth = curr->lockdep_depth;
	int i;

	printk("depth: %u\n", depth + 1);
	for (i = get_first_held_lock(curr, hlock_next); i < depth; i++) {
		hlock = curr->held_locks + i;
		chain_key = print_chain_key_iteration(hlock->class_idx, chain_key);

		print_lock(hlock);
	}

	print_chain_key_iteration(hlock_next->class_idx, chain_key);
	print_lock(hlock_next);
}

static void print_chain_keys_chain(struct lock_chain *chain)
{
	int i;
	u64 chain_key = 0;
	int class_id;

	printk("depth: %u\n", chain->depth);
	for (i = 0; i < chain->depth; i++) {
		class_id = chain_hlocks[chain->base + i];
		chain_key = print_chain_key_iteration(class_id + 1, chain_key);

		print_lock_name(lock_classes + class_id);
		printk("\n");
	}
}

static void print_collision(struct task_struct *curr,
			struct held_lock *hlock_next,
			struct lock_chain *chain)
{
	printk("\n");
	pr_warn("============================\n");
	pr_warn("WARNING: chain_key collision\n");
	print_kernel_ident();
	pr_warn("----------------------------\n");
	printk("%s/%d: ", current->comm, task_pid_nr(current));
	printk("Hash chain already cached but the contents don't match!\n");

	printk("Held locks:");
	print_chain_keys_held_locks(curr, hlock_next);

	printk("Locks in cached chain:");
	print_chain_keys_chain(chain);

	printk("\nstack backtrace:\n");
	dump_stack();
}
#endif

/*
 * Checks whether the chain and the current held locks are consistent
 * in depth and also in content. If they are not it most likely means
 * that there was a collision during the calculation of the chain_key.
 * Returns: 0 not passed, 1 passed
 */
static int check_no_collision(struct task_struct *curr,
			struct held_lock *hlock,
			struct lock_chain *chain)
{
#ifdef CONFIG_DEBUG_LOCKDEP
	int i, j, id;

	i = get_first_held_lock(curr, hlock);

	if (DEBUG_LOCKS_WARN_ON(chain->depth != curr->lockdep_depth - (i - 1))) {
		print_collision(curr, hlock, chain);
		return 0;
	}

	for (j = 0; j < chain->depth - 1; j++, i++) {
		id = curr->held_locks[i].class_idx - 1;

		if (DEBUG_LOCKS_WARN_ON(chain_hlocks[chain->base + j] != id)) {
			print_collision(curr, hlock, chain);
			return 0;
		}
	}
#endif
	return 1;
}

/*
 * Look up a dependency chain. If the key is not present yet then
 * add it and return 1 - in this case the new dependency chain is
 * validated. If the key is already hashed, return 0.
 * (On return with 1 graph_lock is held.)
 */
static inline int lookup_chain_cache(struct task_struct *curr,
				     struct held_lock *hlock,
				     u64 chain_key)
{
	struct lock_class *class = hlock_class(hlock);
	struct hlist_head *hash_head = chainhashentry(chain_key);
	struct lock_chain *chain;
	int i, j;

	/*
	 * We might need to take the graph lock, ensure we've got IRQs
	 * disabled to make this an IRQ-safe lock.. for recursion reasons
	 * lockdep won't complain about its own locking errors.
	 */
	if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
		return 0;
	/*
	 * We can walk it lock-free, because entries only get added
	 * to the hash:
	 */
	hlist_for_each_entry_rcu(chain, hash_head, entry) {
		if (chain->chain_key == chain_key) {
cache_hit:
			debug_atomic_inc(chain_lookup_hits);
			if (!check_no_collision(curr, hlock, chain))
				return 0;

			if (very_verbose(class))
				printk("\nhash chain already cached, key: "
					"%016Lx tail class: [%p] %s\n",
					(unsigned long long)chain_key,
					class->key, class->name);
			return 0;
		}
	}
	if (very_verbose(class))
		printk("\nnew hash chain, key: %016Lx tail class: [%p] %s\n",
			(unsigned long long)chain_key, class->key, class->name);
	/*
	 * Allocate a new chain entry from the static array, and add
	 * it to the hash:
	 */
	if (!graph_lock())
		return 0;
	/*
	 * We have to walk the chain again locked - to avoid duplicates:
	 */
	hlist_for_each_entry(chain, hash_head, entry) {
		if (chain->chain_key == chain_key) {
			graph_unlock();
			goto cache_hit;
		}
	}
	if (unlikely(nr_lock_chains >= MAX_LOCKDEP_CHAINS)) {
		if (!debug_locks_off_graph_unlock())
			return 0;

		print_lockdep_off("BUG: MAX_LOCKDEP_CHAINS too low!");
		dump_stack();
		return 0;
	}
	chain = lock_chains + nr_lock_chains++;
	chain->chain_key = chain_key;
	chain->irq_context = hlock->irq_context;
	i = get_first_held_lock(curr, hlock);
	chain->depth = curr->lockdep_depth + 1 - i;

	BUILD_BUG_ON((1UL << 24) <= ARRAY_SIZE(chain_hlocks));
	BUILD_BUG_ON((1UL << 6)  <= ARRAY_SIZE(curr->held_locks));
	BUILD_BUG_ON((1UL << 8*sizeof(chain_hlocks[0])) <= ARRAY_SIZE(lock_classes));

	if (likely(nr_chain_hlocks + chain->depth <= MAX_LOCKDEP_CHAIN_HLOCKS)) {
		chain->base = nr_chain_hlocks;
		for (j = 0; j < chain->depth - 1; j++, i++) {
			int lock_id = curr->held_locks[i].class_idx - 1;
			chain_hlocks[chain->base + j] = lock_id;
		}
		chain_hlocks[chain->base + j] = class - lock_classes;
	}

	if (nr_chain_hlocks < MAX_LOCKDEP_CHAIN_HLOCKS)
		nr_chain_hlocks += chain->depth;

#ifdef CONFIG_DEBUG_LOCKDEP
	/*
	 * Important for check_no_collision().
	 */
	if (unlikely(nr_chain_hlocks > MAX_LOCKDEP_CHAIN_HLOCKS)) {
		if (!debug_locks_off_graph_unlock())
			return 0;

		print_lockdep_off("BUG: MAX_LOCKDEP_CHAIN_HLOCKS too low!");
		dump_stack();
		return 0;
	}
#endif

	hlist_add_head_rcu(&chain->entry, hash_head);
	debug_atomic_inc(chain_lookup_misses);
	inc_chains();

	return 1;
}

static int validate_chain(struct task_struct *curr, struct lockdep_map *lock,
		struct held_lock *hlock, int chain_head, u64 chain_key)
{
	/*
	 * Trylock needs to maintain the stack of held locks, but it
	 * does not add new dependencies, because trylock can be done
	 * in any order.
	 *
	 * We look up the chain_key and do the O(N^2) check and update of
	 * the dependencies only if this is a new dependency chain.
	 * (If lookup_chain_cache() returns with 1 it acquires
	 * graph_lock for us)
	 */
	if (!hlock->trylock && hlock->check &&
	    lookup_chain_cache(curr, hlock, chain_key)) {
		/*
		 * Check whether last held lock:
		 *
		 * - is irq-safe, if this lock is irq-unsafe
		 * - is softirq-safe, if this lock is hardirq-unsafe
		 *
		 * And check whether the new lock's dependency graph
		 * could lead back to the previous lock.
		 *
		 * any of these scenarios could lead to a deadlock. If
		 * All validations
		 */
		int ret = check_deadlock(curr, hlock, lock, hlock->read);

		if (!ret)
			return 0;
		/*
		 * Mark recursive read, as we jump over it when
		 * building dependencies (just like we jump over
		 * trylock entries):
		 */
		if (ret == 2)
			hlock->read = 2;
		/*
		 * Add dependency only if this lock is not the head
		 * of the chain, and if it's not a secondary read-lock:
		 */
		if (!chain_head && ret != 2)
			if (!check_prevs_add(curr, hlock))
				return 0;
		graph_unlock();
	} else
		/* after lookup_chain_cache(): */
		if (unlikely(!debug_locks))
			return 0;

	return 1;
}
#else
static inline int validate_chain(struct task_struct *curr,
	       	struct lockdep_map *lock, struct held_lock *hlock,
		int chain_head, u64 chain_key)
{
	return 1;
}
#endif

/*
 * We are building curr_chain_key incrementally, so double-check
 * it from scratch, to make sure that it's done correctly:
 */
static void check_chain_key(struct task_struct *curr)
{
#ifdef CONFIG_DEBUG_LOCKDEP
	struct held_lock *hlock, *prev_hlock = NULL;
	unsigned int i;
	u64 chain_key = 0;

	for (i = 0; i < curr->lockdep_depth; i++) {
		hlock = curr->held_locks + i;
		if (chain_key != hlock->prev_chain_key) {
			debug_locks_off();
			/*
			 * We got mighty confused, our chain keys don't match
			 * with what we expect, someone trample on our task state?
			 */
			WARN(1, "hm#1, depth: %u [%u], %016Lx != %016Lx\n",
				curr->lockdep_depth, i,
				(unsigned long long)chain_key,
				(unsigned long long)hlock->prev_chain_key);
			return;
		}
		/*
		 * Whoops ran out of static storage again?
		 */
		if (DEBUG_LOCKS_WARN_ON(hlock->class_idx > MAX_LOCKDEP_KEYS))
			return;

		if (prev_hlock && (prev_hlock->irq_context !=
							hlock->irq_context))
			chain_key = 0;
		chain_key = iterate_chain_key(chain_key, hlock->class_idx);
		prev_hlock = hlock;
	}
	if (chain_key != curr->curr_chain_key) {
		debug_locks_off();
		/*
		 * More smoking hash instead of calculating it, damn see these
		 * numbers float.. I bet that a pink elephant stepped on my memory.
		 */
		WARN(1, "hm#2, depth: %u [%u], %016Lx != %016Lx\n",
			curr->lockdep_depth, i,
			(unsigned long long)chain_key,
			(unsigned long long)curr->curr_chain_key);
	}
#endif
}

static void
print_usage_bug_scenario(struct held_lock *lock)
{
	struct lock_class *class = hlock_class(lock);

	printk(" Possible unsafe locking scenario:\n\n");
	printk("       CPU0\n");
	printk("       ----\n");
	printk("  lock(");
	__print_lock_name(class);
	printk(KERN_CONT ");\n");
	printk("  <Interrupt>\n");
	printk("    lock(");
	__print_lock_name(class);
	printk(KERN_CONT ");\n");
	printk("\n *** DEADLOCK ***\n\n");
}

static int
print_usage_bug(struct task_struct *curr, struct held_lock *this,
		enum lock_usage_bit prev_bit, enum lock_usage_bit new_bit)
{
	if (!debug_locks_off_graph_unlock() || debug_locks_silent)
		return 0;

	printk("\n");
	pr_warn("================================\n");
	pr_warn("WARNING: inconsistent lock state\n");
	print_kernel_ident();
	pr_warn("--------------------------------\n");

	printk("inconsistent {%s} -> {%s} usage.\n",
		usage_str[prev_bit], usage_str[new_bit]);

	printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] takes:\n",
		curr->comm, task_pid_nr(curr),
		trace_hardirq_context(curr), hardirq_count() >> HARDIRQ_SHIFT,
		trace_softirq_context(curr), softirq_count() >> SOFTIRQ_SHIFT,
		trace_hardirqs_enabled(curr),
		trace_softirqs_enabled(curr));
	print_lock(this);

	printk("{%s} state was registered at:\n", usage_str[prev_bit]);
	print_stack_trace(hlock_class(this)->usage_traces + prev_bit, 1);

	print_irqtrace_events(curr);
	printk("\nother info that might help us debug this:\n");
	print_usage_bug_scenario(this);

	lockdep_print_held_locks(curr);

	printk("\nstack backtrace:\n");
	dump_stack();

	return 0;
}

/*
 * Print out an error if an invalid bit is set:
 */
static inline int
valid_state(struct task_struct *curr, struct held_lock *this,
	    enum lock_usage_bit new_bit, enum lock_usage_bit bad_bit)
{
	if (unlikely(hlock_class(this)->usage_mask & (1 << bad_bit)))
		return print_usage_bug(curr, this, bad_bit, new_bit);
	return 1;
}

static int mark_lock(struct task_struct *curr, struct held_lock *this,
		     enum lock_usage_bit new_bit);

#if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING)

/*
 * print irq inversion bug:
 */
static int
print_irq_inversion_bug(struct task_struct *curr,
			struct lock_list *root, struct lock_list *other,
			struct held_lock *this, int forwards,
			const char *irqclass)
{
	struct lock_list *entry = other;
	struct lock_list *middle = NULL;
	int depth;

	if (!debug_locks_off_graph_unlock() || debug_locks_silent)
		return 0;

	printk("\n");
	pr_warn("========================================================\n");
	pr_warn("WARNING: possible irq lock inversion dependency detected\n");
	print_kernel_ident();
	pr_warn("--------------------------------------------------------\n");
	printk("%s/%d just changed the state of lock:\n",
		curr->comm, task_pid_nr(curr));
	print_lock(this);
	if (forwards)
		printk("but this lock took another, %s-unsafe lock in the past:\n", irqclass);
	else
		printk("but this lock was taken by another, %s-safe lock in the past:\n", irqclass);
	print_lock_name(other->class);
	printk("\n\nand interrupts could create inverse lock ordering between them.\n\n");

	printk("\nother info that might help us debug this:\n");

	/* Find a middle lock (if one exists) */
	depth = get_lock_depth(other);
	do {
		if (depth == 0 && (entry != root)) {
			printk("lockdep:%s bad path found in chain graph\n", __func__);
			break;
		}
		middle = entry;
		entry = get_lock_parent(entry);
		depth--;
	} while (entry && entry != root && (depth >= 0));
	if (forwards)
		print_irq_lock_scenario(root, other,
			middle ? middle->class : root->class, other->class);
	else
		print_irq_lock_scenario(other, root,
			middle ? middle->class : other->class, root->class);

	lockdep_print_held_locks(curr);

	printk("\nthe shortest dependencies between 2nd lock and 1st lock:\n");
	if (!save_trace(&root->trace))
		return 0;
	print_shortest_lock_dependencies(other, root);

	printk("\nstack backtrace:\n");
	dump_stack();

	return 0;
}

/*
 * Prove that in the forwards-direction subgraph starting at <this>
 * there is no lock matching <mask>:
 */
static int
check_usage_forwards(struct task_struct *curr, struct held_lock *this,
		     enum lock_usage_bit bit, const char *irqclass)
{
	int ret;
	struct lock_list root;
	struct lock_list *uninitialized_var(target_entry);

	root.parent = NULL;
	root.class = hlock_class(this);
	ret = find_usage_forwards(&root, bit, &target_entry);
	if (ret < 0)
		return print_bfs_bug(ret);
	if (ret == 1)
		return ret;

	return print_irq_inversion_bug(curr, &root, target_entry,
					this, 1, irqclass);
}

/*
 * Prove that in the backwards-direction subgraph starting at <this>
 * there is no lock matching <mask>:
 */
static int
check_usage_backwards(struct task_struct *curr, struct held_lock *this,
		      enum lock_usage_bit bit, const char *irqclass)
{
	int ret;
	struct lock_list root;
	struct lock_list *uninitialized_var(target_entry);

	root.parent = NULL;
	root.class = hlock_class(this);
	ret = find_usage_backwards(&root, bit, &target_entry);
	if (ret < 0)
		return print_bfs_bug(ret);
	if (ret == 1)
		return ret;

	return print_irq_inversion_bug(curr, &root, target_entry,
					this, 0, irqclass);
}

void print_irqtrace_events(struct task_struct *curr)
{
	printk("irq event stamp: %u\n", curr->irq_events);
	printk("hardirqs last  enabled at (%u): [<%p>] %pS\n",
		curr->hardirq_enable_event, (void *)curr->hardirq_enable_ip,
		(void *)curr->hardirq_enable_ip);
	printk("hardirqs last disabled at (%u): [<%p>] %pS\n",
		curr->hardirq_disable_event, (void *)curr->hardirq_disable_ip,
		(void *)curr->hardirq_disable_ip);
	printk("softirqs last  enabled at (%u): [<%p>] %pS\n",
		curr->softirq_enable_event, (void *)curr->softirq_enable_ip,
		(void *)curr->softirq_enable_ip);
	printk("softirqs last disabled at (%u): [<%p>] %pS\n",
		curr->softirq_disable_event, (void *)curr->softirq_disable_ip,
		(void *)curr->softirq_disable_ip);
}

static int HARDIRQ_verbose(struct lock_class *class)
{
#if HARDIRQ_VERBOSE
	return class_filter(class);
#endif
	return 0;
}

static int SOFTIRQ_verbose(struct lock_class *class)
{
#if SOFTIRQ_VERBOSE
	return class_filter(class);
#endif
	return 0;
}

static int RECLAIM_FS_verbose(struct lock_class *class)
{
#if RECLAIM_VERBOSE
	return class_filter(class);
#endif
	return 0;
}

#define STRICT_READ_CHECKS	1

static int (*state_verbose_f[])(struct lock_class *class) = {
#define LOCKDEP_STATE(__STATE) \
	__STATE##_verbose,
#include "lockdep_states.h"
#undef LOCKDEP_STATE
};

static inline int state_verbose(enum lock_usage_bit bit,
				struct lock_class *class)
{
	return state_verbose_f[bit >> 2](class);
}

typedef int (*check_usage_f)(struct task_struct *, struct held_lock *,
			     enum lock_usage_bit bit, const char *name);

static int
mark_lock_irq(struct task_struct *curr, struct held_lock *this,
		enum lock_usage_bit new_bit)
{
	int excl_bit = exclusive_bit(new_bit);
	int read = new_bit & 1;
	int dir = new_bit & 2;

	/*
	 * mark USED_IN has to look forwards -- to ensure no dependency
	 * has ENABLED state, which would allow recursion deadlocks.
	 *
	 * mark ENABLED has to look backwards -- to ensure no dependee
	 * has USED_IN state, which, again, would allow  recursion deadlocks.
	 */
	check_usage_f usage = dir ?
		check_usage_backwards : check_usage_forwards;

	/*
	 * Validate that this particular lock does not have conflicting
	 * usage states.
	 */
	if (!valid_state(curr, this, new_bit, excl_bit))
		return 0;

	/*
	 * Validate that the lock dependencies don't have conflicting usage
	 * states.
	 */
	if ((!read || !dir || STRICT_READ_CHECKS) &&
			!usage(curr, this, excl_bit, state_name(new_bit & ~1)))
		return 0;

	/*
	 * Check for read in write conflicts
	 */
	if (!read) {
		if (!valid_state(curr, this, new_bit, excl_bit + 1))
			return 0;

		if (STRICT_READ_CHECKS &&
			!usage(curr, this, excl_bit + 1,
				state_name(new_bit + 1)))
			return 0;
	}

	if (state_verbose(new_bit, hlock_class(this)))
		return 2;

	return 1;
}

enum mark_type {
#define LOCKDEP_STATE(__STATE)	__STATE,
#include "lockdep_states.h"
#undef LOCKDEP_STATE
};

/*
 * Mark all held locks with a usage bit:
 */
static int
mark_held_locks(struct task_struct *curr, enum mark_type mark)
{
	enum lock_usage_bit usage_bit;
	struct held_lock *hlock;
	int i;

	for (i = 0; i < curr->lockdep_depth; i++) {
		hlock = curr->held_locks + i;

		usage_bit = 2 + (mark << 2); /* ENABLED */
		if (hlock->read)
			usage_bit += 1; /* READ */

		BUG_ON(usage_bit >= LOCK_USAGE_STATES);

		if (!hlock->check)
			continue;

		if (!mark_lock(curr, hlock, usage_bit))
			return 0;
	}

	return 1;
}

/*
 * Hardirqs will be enabled:
 */
static void __trace_hardirqs_on_caller(unsigned long ip)
{
	struct task_struct *curr = current;

	/* we'll do an OFF -> ON transition: */
	curr->hardirqs_enabled = 1;

	/*
	 * We are going to turn hardirqs on, so set the
	 * usage bit for all held locks:
	 */
	if (!mark_held_locks(curr, HARDIRQ))
		return;
	/*
	 * If we have softirqs enabled, then set the usage
	 * bit for all held locks. (disabled hardirqs prevented
	 * this bit from being set before)
	 */
	if (curr->softirqs_enabled)
		if (!mark_held_locks(curr, SOFTIRQ))
			return;

	curr->hardirq_enable_ip = ip;
	curr->hardirq_enable_event = ++curr->irq_events;
	debug_atomic_inc(hardirqs_on_events);
}

__visible void trace_hardirqs_on_caller(unsigned long ip)
{
	time_hardirqs_on(CALLER_ADDR0, ip);

	if (unlikely(!debug_locks || current->lockdep_recursion))
		return;

	if (unlikely(current->hardirqs_enabled)) {
		/*
		 * Neither irq nor preemption are disabled here
		 * so this is racy by nature but losing one hit
		 * in a stat is not a big deal.
		 */
		__debug_atomic_inc(redundant_hardirqs_on);
		return;
	}

	/*
	 * We're enabling irqs and according to our state above irqs weren't
	 * already enabled, yet we find the hardware thinks they are in fact
	 * enabled.. someone messed up their IRQ state tracing.
	 */
	if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
		return;

	/*
	 * See the fine text that goes along with this variable definition.
	 */
	if (DEBUG_LOCKS_WARN_ON(unlikely(early_boot_irqs_disabled)))
		return;

	/*
	 * Can't allow enabling interrupts while in an interrupt handler,
	 * that's general bad form and such. Recursion, limited stack etc..
	 */
	if (DEBUG_LOCKS_WARN_ON(current->hardirq_context))
		return;

	current->lockdep_recursion = 1;
	__trace_hardirqs_on_caller(ip);
	current->lockdep_recursion = 0;
}
EXPORT_SYMBOL(trace_hardirqs_on_caller);

void trace_hardirqs_on(void)
{
	trace_hardirqs_on_caller(CALLER_ADDR0);
}
EXPORT_SYMBOL(trace_hardirqs_on);

/*
 * Hardirqs were disabled:
 */
__visible void trace_hardirqs_off_caller(unsigned long ip)
{
	struct task_struct *curr = current;

	time_hardirqs_off(CALLER_ADDR0, ip);

	if (unlikely(!debug_locks || current->lockdep_recursion))
		return;

	/*
	 * So we're supposed to get called after you mask local IRQs, but for
	 * some reason the hardware doesn't quite think you did a proper job.
	 */
	if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
		return;

	if (curr->hardirqs_enabled) {
		/*
		 * We have done an ON -> OFF transition:
		 */
		curr->hardirqs_enabled = 0;
		curr->hardirq_disable_ip = ip;
		curr->hardirq_disable_event = ++curr->irq_events;
		debug_atomic_inc(hardirqs_off_events);
	} else
		debug_atomic_inc(redundant_hardirqs_off);
}
EXPORT_SYMBOL(trace_hardirqs_off_caller);

void trace_hardirqs_off(void)
{
	trace_hardirqs_off_caller(CALLER_ADDR0);
}
EXPORT_SYMBOL(trace_hardirqs_off);

/*
 * Softirqs will be enabled:
 */
void trace_softirqs_on(unsigned long ip)
{
	struct task_struct *curr = current;

	if (unlikely(!debug_locks || current->lockdep_recursion))
		return;

	/*
	 * We fancy IRQs being disabled here, see softirq.c, avoids
	 * funny state and nesting things.
	 */
	if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
		return;

	if (curr->softirqs_enabled) {
		debug_atomic_inc(redundant_softirqs_on);
		return;
	}

	current->lockdep_recursion = 1;
	/*
	 * We'll do an OFF -> ON transition:
	 */
	curr->softirqs_enabled = 1;
	curr->softirq_enable_ip = ip;
	curr->softirq_enable_event = ++curr->irq_events;
	debug_atomic_inc(softirqs_on_events);
	/*
	 * We are going to turn softirqs on, so set the
	 * usage bit for all held locks, if hardirqs are
	 * enabled too:
	 */
	if (curr->hardirqs_enabled)
		mark_held_locks(curr, SOFTIRQ);
	current->lockdep_recursion = 0;
}

/*
 * Softirqs were disabled:
 */
void trace_softirqs_off(unsigned long ip)
{
	struct task_struct *curr = current;

	if (unlikely(!debug_locks || current->lockdep_recursion))
		return;

	/*
	 * We fancy IRQs being disabled here, see softirq.c
	 */
	if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
		return;

	if (curr->softirqs_enabled) {
		/*
		 * We have done an ON -> OFF transition:
		 */
		curr->softirqs_enabled = 0;
		curr->softirq_disable_ip = ip;
		curr->softirq_disable_event = ++curr->irq_events;
		debug_atomic_inc(softirqs_off_events);
		/*
		 * Whoops, we wanted softirqs off, so why aren't they?
		 */
		DEBUG_LOCKS_WARN_ON(!softirq_count());
	} else
		debug_atomic_inc(redundant_softirqs_off);
}

static void __lockdep_trace_alloc(gfp_t gfp_mask, unsigned long flags)
{
	struct task_struct *curr = current;

	if (unlikely(!debug_locks))
		return;

	gfp_mask = current_gfp_context(gfp_mask);

	/* no reclaim without waiting on it */
	if (!(gfp_mask & __GFP_DIRECT_RECLAIM))
		return;

	/* this guy won't enter reclaim */
	if ((curr->flags & PF_MEMALLOC) && !(gfp_mask & __GFP_NOMEMALLOC))
		return;

	/* We're only interested __GFP_FS allocations for now */
	if (!(gfp_mask & __GFP_FS) || (curr->flags & PF_MEMALLOC_NOFS))
		return;

	/*
	 * Oi! Can't be having __GFP_FS allocations with IRQs disabled.
	 */
	if (DEBUG_LOCKS_WARN_ON(irqs_disabled_flags(flags)))
		return;

	/* Disable lockdep if explicitly requested */
	if (gfp_mask & __GFP_NOLOCKDEP)
		return;

	mark_held_locks(curr, RECLAIM_FS);
}

static void check_flags(unsigned long flags);

void lockdep_trace_alloc(gfp_t gfp_mask)
{
	unsigned long flags;

	if (unlikely(current->lockdep_recursion))
		return;

	raw_local_irq_save(flags);
	check_flags(flags);
	current->lockdep_recursion = 1;
	__lockdep_trace_alloc(gfp_mask, flags);
	current->lockdep_recursion = 0;
	raw_local_irq_restore(flags);
}

static int mark_irqflags(struct task_struct *curr, struct held_lock *hlock)
{
	/*
	 * If non-trylock use in a hardirq or softirq context, then
	 * mark the lock as used in these contexts:
	 */
	if (!hlock->trylock) {
		if (hlock->read) {
			if (curr->hardirq_context)
				if (!mark_lock(curr, hlock,
						LOCK_USED_IN_HARDIRQ_READ))
					return 0;
			if (curr->softirq_context)
				if (!mark_lock(curr, hlock,
						LOCK_USED_IN_SOFTIRQ_READ))
					return 0;
		} else {
			if (curr->hardirq_context)
				if (!mark_lock(curr, hlock, LOCK_USED_IN_HARDIRQ))
					return 0;
			if (curr->softirq_context)
				if (!mark_lock(curr, hlock, LOCK_USED_IN_SOFTIRQ))
					return 0;
		}
	}
	if (!hlock->hardirqs_off) {
		if (hlock->read) {
			if (!mark_lock(curr, hlock,
					LOCK_ENABLED_HARDIRQ_READ))
				return 0;
			if (curr->softirqs_enabled)
				if (!mark_lock(curr, hlock,
						LOCK_ENABLED_SOFTIRQ_READ))
					return 0;
		} else {
			if (!mark_lock(curr, hlock,
					LOCK_ENABLED_HARDIRQ))
				return 0;
			if (curr->softirqs_enabled)
				if (!mark_lock(curr, hlock,
						LOCK_ENABLED_SOFTIRQ))
					return 0;
		}
	}

	/*
	 * We reuse the irq context infrastructure more broadly as a general
	 * context checking code. This tests GFP_FS recursion (a lock taken
	 * during reclaim for a GFP_FS allocation is held over a GFP_FS
	 * allocation).
	 */
	if (!hlock->trylock && (curr->lockdep_reclaim_gfp & __GFP_FS)) {
		if (hlock->read) {
			if (!mark_lock(curr, hlock, LOCK_USED_IN_RECLAIM_FS_READ))
					return 0;
		} else {
			if (!mark_lock(curr, hlock, LOCK_USED_IN_RECLAIM_FS))
					return 0;
		}
	}

	return 1;
}

static inline unsigned int task_irq_context(struct task_struct *task)
{
	return 2 * !!task->hardirq_context + !!task->softirq_context;
}

static int separate_irq_context(struct task_struct *curr,
		struct held_lock *hlock)
{
	unsigned int depth = curr->lockdep_depth;

	/*
	 * Keep track of points where we cross into an interrupt context:
	 */
	if (depth) {
		struct held_lock *prev_hlock;

		prev_hlock = curr->held_locks + depth-1;
		/*
		 * If we cross into another context, reset the
		 * hash key (this also prevents the checking and the
		 * adding of the dependency to 'prev'):
		 */
		if (prev_hlock->irq_context != hlock->irq_context)
			return 1;
	}
	return 0;
}

#else /* defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) */

static inline
int mark_lock_irq(struct task_struct *curr, struct held_lock *this,
		enum lock_usage_bit new_bit)
{
	WARN_ON(1); /* Impossible innit? when we don't have TRACE_IRQFLAG */
	return 1;
}

static inline int mark_irqflags(struct task_struct *curr,
		struct held_lock *hlock)
{
	return 1;
}

static inline unsigned int task_irq_context(struct task_struct *task)
{
	return 0;
}

static inline int separate_irq_context(struct task_struct *curr,
		struct held_lock *hlock)
{
	return 0;
}

void lockdep_trace_alloc(gfp_t gfp_mask)
{
}

#endif /* defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) */

/*
 * Mark a lock with a usage bit, and validate the state transition:
 */
static int mark_lock(struct task_struct *curr, struct held_lock *this,
			     enum lock_usage_bit new_bit)
{
	unsigned int new_mask = 1 << new_bit, ret = 1;

	/*
	 * If already set then do not dirty the cacheline,
	 * nor do any checks:
	 */
	if (likely(hlock_class(this)->usage_mask & new_mask))
		return 1;

	if (!graph_lock())
		return 0;
	/*
	 * Make sure we didn't race:
	 */
	if (unlikely(hlock_class(this)->usage_mask & new_mask)) {
		graph_unlock();
		return 1;
	}

	hlock_class(this)->usage_mask |= new_mask;

	if (!save_trace(hlock_class(this)->usage_traces + new_bit))
		return 0;

	switch (new_bit) {
#define LOCKDEP_STATE(__STATE)			\
	case LOCK_USED_IN_##__STATE:		\
	case LOCK_USED_IN_##__STATE##_READ:	\
	case LOCK_ENABLED_##__STATE:		\
	case LOCK_ENABLED_##__STATE##_READ:
#include "lockdep_states.h"
#undef LOCKDEP_STATE
		ret = mark_lock_irq(curr, this, new_bit);
		if (!ret)
			return 0;
		break;
	case LOCK_USED:
		debug_atomic_dec(nr_unused_locks);
		break;
	default:
		if (!debug_locks_off_graph_unlock())
			return 0;
		WARN_ON(1);
		return 0;
	}

	graph_unlock();

	/*
	 * We must printk outside of the graph_lock:
	 */
	if (ret == 2) {
		printk("\nmarked lock as {%s}:\n", usage_str[new_bit]);
		print_lock(this);
		print_irqtrace_events(curr);
		dump_stack();
	}

	return ret;
}

/*
 * Initialize a lock instance's lock-class mapping info:
 */
void lockdep_init_map(struct lockdep_map *lock, const char *name,
		      struct lock_class_key *key, int subclass)
{
	int i;

	kmemcheck_mark_initialized(lock, sizeof(*lock));

	for (i = 0; i < NR_LOCKDEP_CACHING_CLASSES; i++)
		lock->class_cache[i] = NULL;

#ifdef CONFIG_LOCK_STAT
	lock->cpu = raw_smp_processor_id();
#endif

	/*
	 * Can't be having no nameless bastards around this place!
	 */
	if (DEBUG_LOCKS_WARN_ON(!name)) {
		lock->name = "NULL";
		return;
	}

	lock->name = name;

	/*
	 * No key, no joy, we need to hash something.
	 */
	if (DEBUG_LOCKS_WARN_ON(!key))
		return;
	/*
	 * Sanity check, the lock-class key must be persistent:
	 */
	if (!static_obj(key)) {
		printk("BUG: key %p not in .data!\n", key);
		/*
		 * What it says above ^^^^^, I suggest you read it.
		 */
		DEBUG_LOCKS_WARN_ON(1);
		return;
	}
	lock->key = key;

	if (unlikely(!debug_locks))
		return;

	if (subclass) {
		unsigned long flags;

		if (DEBUG_LOCKS_WARN_ON(current->lockdep_recursion))
			return;

		raw_local_irq_save(flags);
		current->lockdep_recursion = 1;
		register_lock_class(lock, subclass, 1);
		current->lockdep_recursion = 0;
		raw_local_irq_restore(flags);
	}
}
EXPORT_SYMBOL_GPL(lockdep_init_map);

struct lock_class_key __lockdep_no_validate__;
EXPORT_SYMBOL_GPL(__lockdep_no_validate__);

static int
print_lock_nested_lock_not_held(struct task_struct *curr,
				struct held_lock *hlock,
				unsigned long ip)
{
	if (!debug_locks_off())
		return 0;
	if (debug_locks_silent)
		return 0;

	printk("\n");
	pr_warn("==================================\n");
	pr_warn("WARNING: Nested lock was not taken\n");
	print_kernel_ident();
	pr_warn("----------------------------------\n");

	printk("%s/%d is trying to lock:\n", curr->comm, task_pid_nr(curr));
	print_lock(hlock);

	printk("\nbut this task is not holding:\n");
	printk("%s\n", hlock->nest_lock->name);

	printk("\nstack backtrace:\n");
	dump_stack();

	printk("\nother info that might help us debug this:\n");
	lockdep_print_held_locks(curr);

	printk("\nstack backtrace:\n");
	dump_stack();

	return 0;
}

static int __lock_is_held(struct lockdep_map *lock, int read);

/*
 * This gets called for every mutex_lock*()/spin_lock*() operation.
 * We maintain the dependency maps and validate the locking attempt:
 */
static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass,
			  int trylock, int read, int check, int hardirqs_off,
			  struct lockdep_map *nest_lock, unsigned long ip,
			  int references, int pin_count)
{
	struct task_struct *curr = current;
	struct lock_class *class = NULL;
	struct held_lock *hlock;
	unsigned int depth;
	int chain_head = 0;
	int class_idx;
	u64 chain_key;

	if (unlikely(!debug_locks))
		return 0;

	/*
	 * Lockdep should run with IRQs disabled, otherwise we could
	 * get an interrupt which would want to take locks, which would
	 * end up in lockdep and have you got a head-ache already?
	 */
	if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
		return 0;

	if (!prove_locking || lock->key == &__lockdep_no_validate__)
		check = 0;

	if (subclass < NR_LOCKDEP_CACHING_CLASSES)
		class = lock->class_cache[subclass];
	/*
	 * Not cached?
	 */
	if (unlikely(!class)) {
		class = register_lock_class(lock, subclass, 0);
		if (!class)
			return 0;
	}
	atomic_inc((atomic_t *)&class->ops);
	if (very_verbose(class)) {
		printk("\nacquire class [%p] %s", class->key, class->name);
		if (class->name_version > 1)
			printk(KERN_CONT "#%d", class->name_version);
		printk(KERN_CONT "\n");
		dump_stack();
	}

	/*
	 * Add the lock to the list of currently held locks.
	 * (we dont increase the depth just yet, up until the
	 * dependency checks are done)
	 */
	depth = curr->lockdep_depth;
	/*
	 * Ran out of static storage for our per-task lock stack again have we?
	 */
	if (DEBUG_LOCKS_WARN_ON(depth >= MAX_LOCK_DEPTH))
		return 0;

	class_idx = class - lock_classes + 1;

	if (depth) {
		hlock = curr->held_locks + depth - 1;
		if (hlock->class_idx == class_idx && nest_lock) {
			if (hlock->references) {
				/*
				 * Check: unsigned int references:12, overflow.
				 */
				if (DEBUG_LOCKS_WARN_ON(hlock->references == (1 << 12)-1))
					return 0;

				hlock->references++;
			} else {
				hlock->references = 2;
			}

			return 1;
		}
	}

	hlock = curr->held_locks + depth;
	/*
	 * Plain impossible, we just registered it and checked it weren't no
	 * NULL like.. I bet this mushroom I ate was good!
	 */
	if (DEBUG_LOCKS_WARN_ON(!class))
		return 0;
	hlock->class_idx = class_idx;
	hlock->acquire_ip = ip;
	hlock->instance = lock;
	hlock->nest_lock = nest_lock;
	hlock->irq_context = task_irq_context(curr);
	hlock->trylock = trylock;
	hlock->read = read;
	hlock->check = check;
	hlock->hardirqs_off = !!hardirqs_off;
	hlock->references = references;
#ifdef CONFIG_LOCK_STAT
	hlock->waittime_stamp = 0;
	hlock->holdtime_stamp = lockstat_clock();
#endif
	hlock->pin_count = pin_count;

	if (check && !mark_irqflags(curr, hlock))
		return 0;

	/* mark it as used: */
	if (!mark_lock(curr, hlock, LOCK_USED))
		return 0;

	/*
	 * Calculate the chain hash: it's the combined hash of all the
	 * lock keys along the dependency chain. We save the hash value
	 * at every step so that we can get the current hash easily
	 * after unlock. The chain hash is then used to cache dependency
	 * results.
	 *
	 * The 'key ID' is what is the most compact key value to drive
	 * the hash, not class->key.
	 */
	/*
	 * Whoops, we did it again.. ran straight out of our static allocation.
	 */
	if (DEBUG_LOCKS_WARN_ON(class_idx > MAX_LOCKDEP_KEYS))
		return 0;

	chain_key = curr->curr_chain_key;
	if (!depth) {
		/*
		 * How can we have a chain hash when we ain't got no keys?!
		 */
		if (DEBUG_LOCKS_WARN_ON(chain_key != 0))
			return 0;
		chain_head = 1;
	}

	hlock->prev_chain_key = chain_key;
	if (separate_irq_context(curr, hlock)) {
		chain_key = 0;
		chain_head = 1;
	}
	chain_key = iterate_chain_key(chain_key, class_idx);

	if (nest_lock && !__lock_is_held(nest_lock, -1))
		return print_lock_nested_lock_not_held(curr, hlock, ip);

	if (!validate_chain(curr, lock, hlock, chain_head, chain_key))
		return 0;

	curr->curr_chain_key = chain_key;
	curr->lockdep_depth++;
	check_chain_key(curr);
#ifdef CONFIG_DEBUG_LOCKDEP
	if (unlikely(!debug_locks))
		return 0;
#endif
	if (unlikely(curr->lockdep_depth >= MAX_LOCK_DEPTH)) {
		debug_locks_off();
		print_lockdep_off("BUG: MAX_LOCK_DEPTH too low!");
		printk(KERN_DEBUG "depth: %i  max: %lu!\n",
		       curr->lockdep_depth, MAX_LOCK_DEPTH);

		lockdep_print_held_locks(current);
		debug_show_all_locks();
		dump_stack();

		return 0;
	}

	if (unlikely(curr->lockdep_depth > max_lockdep_depth))
		max_lockdep_depth = curr->lockdep_depth;

	return 1;
}

static int
print_unlock_imbalance_bug(struct task_struct *curr, struct lockdep_map *lock,
			   unsigned long ip)
{
	if (!debug_locks_off())
		return 0;
	if (debug_locks_silent)
		return 0;

	printk("\n");
	pr_warn("=====================================\n");
	pr_warn("WARNING: bad unlock balance detected!\n");
	print_kernel_ident();
	pr_warn("-------------------------------------\n");
	printk("%s/%d is trying to release lock (",
		curr->comm, task_pid_nr(curr));
	print_lockdep_cache(lock);
	printk(KERN_CONT ") at:\n");
	print_ip_sym(ip);
	printk("but there are no more locks to release!\n");
	printk("\nother info that might help us debug this:\n");
	lockdep_print_held_locks(curr);

	printk("\nstack backtrace:\n");
	dump_stack();

	return 0;
}

static int match_held_lock(struct held_lock *hlock, struct lockdep_map *lock)
{
	if (hlock->instance == lock)
		return 1;

	if (hlock->references) {
		struct lock_class *class = lock->class_cache[0];

		if (!class)
			class = look_up_lock_class(lock, 0);

		/*
		 * If look_up_lock_class() failed to find a class, we're trying
		 * to test if we hold a lock that has never yet been acquired.
		 * Clearly if the lock hasn't been acquired _ever_, we're not
		 * holding it either, so report failure.
		 */
		if (IS_ERR_OR_NULL(class))
			return 0;

		/*
		 * References, but not a lock we're actually ref-counting?
		 * State got messed up, follow the sites that change ->references
		 * and try to make sense of it.
		 */
		if (DEBUG_LOCKS_WARN_ON(!hlock->nest_lock))
			return 0;

		if (hlock->class_idx == class - lock_classes + 1)
			return 1;
	}

	return 0;
}

/* @depth must not be zero */
static struct held_lock *find_held_lock(struct task_struct *curr,
					struct lockdep_map *lock,
					unsigned int depth, int *idx)
{
	struct held_lock *ret, *hlock, *prev_hlock;
	int i;

	i = depth - 1;
	hlock = curr->held_locks + i;
	ret = hlock;
	if (match_held_lock(hlock, lock))
		goto out;

	ret = NULL;
	for (i--, prev_hlock = hlock--;
	     i >= 0;
	     i--, prev_hlock = hlock--) {
		/*
		 * We must not cross into another context:
		 */
		if (prev_hlock->irq_context != hlock->irq_context) {
			ret = NULL;
			break;
		}
		if (match_held_lock(hlock, lock)) {
			ret = hlock;
			break;
		}
	}

out:
	*idx = i;
	return ret;
}

static int reacquire_held_locks(struct task_struct *curr, unsigned int depth,
			      int idx)
{
	struct held_lock *hlock;

	for (hlock = curr->held_locks + idx; idx < depth; idx++, hlock++) {
		if (!__lock_acquire(hlock->instance,
				    hlock_class(hlock)->subclass,
				    hlock->trylock,
				    hlock->read, hlock->check,
				    hlock->hardirqs_off,
				    hlock->nest_lock, hlock->acquire_ip,
				    hlock->references, hlock->pin_count))
			return 1;
	}
	return 0;
}

static int
__lock_set_class(struct lockdep_map *lock, const char *name,
		 struct lock_class_key *key, unsigned int subclass,
		 unsigned long ip)
{
	struct task_struct *curr = current;
	struct held_lock *hlock;
	struct lock_class *class;
	unsigned int depth;
	int i;

	depth = curr->lockdep_depth;
	/*
	 * This function is about (re)setting the class of a held lock,
	 * yet we're not actually holding any locks. Naughty user!
	 */
	if (DEBUG_LOCKS_WARN_ON(!depth))
		return 0;

	hlock = find_held_lock(curr, lock, depth, &i);
	if (!hlock)
		return print_unlock_imbalance_bug(curr, lock, ip);

	lockdep_init_map(lock, name, key, 0);
	class = register_lock_class(lock, subclass, 0);
	hlock->class_idx = class - lock_classes + 1;

	curr->lockdep_depth = i;
	curr->curr_chain_key = hlock->prev_chain_key;

	if (reacquire_held_locks(curr, depth, i))
		return 0;

	/*
	 * I took it apart and put it back together again, except now I have
	 * these 'spare' parts.. where shall I put them.
	 */
	if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth))
		return 0;
	return 1;
}

static int __lock_downgrade(struct lockdep_map *lock, unsigned long ip)
{
	struct task_struct *curr = current;
	struct held_lock *hlock;
	unsigned int depth;
	int i;

	depth = curr->lockdep_depth;
	/*
	 * This function is about (re)setting the class of a held lock,
	 * yet we're not actually holding any locks. Naughty user!
	 */
	if (DEBUG_LOCKS_WARN_ON(!depth))
		return 0;

	hlock = find_held_lock(curr, lock, depth, &i);
	if (!hlock)
		return print_unlock_imbalance_bug(curr, lock, ip);

	curr->lockdep_depth = i;
	curr->curr_chain_key = hlock->prev_chain_key;

	WARN(hlock->read, "downgrading a read lock");
	hlock->read = 1;
	hlock->acquire_ip = ip;

	if (reacquire_held_locks(curr, depth, i))
		return 0;

	/*
	 * I took it apart and put it back together again, except now I have
	 * these 'spare' parts.. where shall I put them.
	 */
	if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth))
		return 0;
	return 1;
}

/*
 * Remove the lock to the list of currently held locks - this gets
 * called on mutex_unlock()/spin_unlock*() (or on a failed
 * mutex_lock_interruptible()).
 *
 * @nested is an hysterical artifact, needs a tree wide cleanup.
 */
static int
__lock_release(struct lockdep_map *lock, int nested, unsigned long ip)
{
	struct task_struct *curr = current;
	struct held_lock *hlock;
	unsigned int depth;
	int i;

	if (unlikely(!debug_locks))
		return 0;

	depth = curr->lockdep_depth;
	/*
	 * So we're all set to release this lock.. wait what lock? We don't
	 * own any locks, you've been drinking again?
	 */
	if (DEBUG_LOCKS_WARN_ON(depth <= 0))
		 return print_unlock_imbalance_bug(curr, lock, ip);

	/*
	 * Check whether the lock exists in the current stack
	 * of held locks:
	 */
	hlock = find_held_lock(curr, lock, depth, &i);
	if (!hlock)
		return print_unlock_imbalance_bug(curr, lock, ip);

	if (hlock->instance == lock)
		lock_release_holdtime(hlock);

	WARN(hlock->pin_count, "releasing a pinned lock\n");

	if (hlock->references) {
		hlock->references--;
		if (hlock->references) {
			/*
			 * We had, and after removing one, still have
			 * references, the current lock stack is still
			 * valid. We're done!
			 */
			return 1;
		}
	}

	/*
	 * We have the right lock to unlock, 'hlock' points to it.
	 * Now we remove it from the stack, and add back the other
	 * entries (if any), recalculating the hash along the way:
	 */

	curr->lockdep_depth = i;
	curr->curr_chain_key = hlock->prev_chain_key;

	if (reacquire_held_locks(curr, depth, i + 1))
		return 0;

	/*
	 * We had N bottles of beer on the wall, we drank one, but now
	 * there's not N-1 bottles of beer left on the wall...
	 */
	if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth - 1))
		return 0;

	return 1;
}

static int __lock_is_held(struct lockdep_map *lock, int read)
{
	struct task_struct *curr = current;
	int i;

	for (i = 0; i < curr->lockdep_depth; i++) {
		struct held_lock *hlock = curr->held_locks + i;

		if (match_held_lock(hlock, lock)) {
			if (read == -1 || hlock->read == read)
				return 1;

			return 0;
		}
	}

	return 0;
}

static struct pin_cookie __lock_pin_lock(struct lockdep_map *lock)
{
	struct pin_cookie cookie = NIL_COOKIE;
	struct task_struct *curr = current;
	int i;

	if (unlikely(!debug_locks))
		return cookie;

	for (i = 0; i < curr->lockdep_depth; i++) {
		struct held_lock *hlock = curr->held_locks + i;

		if (match_held_lock(hlock, lock)) {
			/*
			 * Grab 16bits of randomness; this is sufficient to not
			 * be guessable and still allows some pin nesting in
			 * our u32 pin_count.
			 */
			cookie.val = 1 + (prandom_u32() >> 16);
			hlock->pin_count += cookie.val;
			return cookie;
		}
	}

	WARN(1, "pinning an unheld lock\n");
	return cookie;
}

static void __lock_repin_lock(struct lockdep_map *lock, struct pin_cookie cookie)
{
	struct task_struct *curr = current;
	int i;

	if (unlikely(!debug_locks))
		return;

	for (i = 0; i < curr->lockdep_depth; i++) {
		struct held_lock *hlock = curr->held_locks + i;

		if (match_held_lock(hlock, lock)) {
			hlock->pin_count += cookie.val;
			return;
		}
	}

	WARN(1, "pinning an unheld lock\n");
}

static void __lock_unpin_lock(struct lockdep_map *lock, struct pin_cookie cookie)
{
	struct task_struct *curr = current;
	int i;

	if (unlikely(!debug_locks))
		return;

	for (i = 0; i < curr->lockdep_depth; i++) {
		struct held_lock *hlock = curr->held_locks + i;

		if (match_held_lock(hlock, lock)) {
			if (WARN(!hlock->pin_count, "unpinning an unpinned lock\n"))
				return;

			hlock->pin_count -= cookie.val;

			if (WARN((int)hlock->pin_count < 0, "pin count corrupted\n"))
				hlock->pin_count = 0;

			return;
		}
	}

	WARN(1, "unpinning an unheld lock\n");
}

/*
 * Check whether we follow the irq-flags state precisely:
 */
static void check_flags(unsigned long flags)
{
#if defined(CONFIG_PROVE_LOCKING) && defined(CONFIG_DEBUG_LOCKDEP) && \
    defined(CONFIG_TRACE_IRQFLAGS)
	if (!debug_locks)
		return;

	if (irqs_disabled_flags(flags)) {
		if (DEBUG_LOCKS_WARN_ON(current->hardirqs_enabled)) {
			printk("possible reason: unannotated irqs-off.\n");
		}
	} else {
		if (DEBUG_LOCKS_WARN_ON(!current->hardirqs_enabled)) {
			printk("possible reason: unannotated irqs-on.\n");
		}
	}

	/*
	 * We dont accurately track softirq state in e.g.
	 * hardirq contexts (such as on 4KSTACKS), so only
	 * check if not in hardirq contexts:
	 */
	if (!hardirq_count()) {
		if (softirq_count()) {
			/* like the above, but with softirqs */
			DEBUG_LOCKS_WARN_ON(current->softirqs_enabled);
		} else {
			/* lick the above, does it taste good? */
			DEBUG_LOCKS_WARN_ON(!current->softirqs_enabled);
		}
	}

	if (!debug_locks)
		print_irqtrace_events(current);
#endif
}

void lock_set_class(struct lockdep_map *lock, const char *name,
		    struct lock_class_key *key, unsigned int subclass,
		    unsigned long ip)
{
	unsigned long flags;

	if (unlikely(current->lockdep_recursion))
		return;

	raw_local_irq_save(flags);
	current->lockdep_recursion = 1;
	check_flags(flags);
	if (__lock_set_class(lock, name, key, subclass, ip))
		check_chain_key(current);
	current->lockdep_recursion = 0;
	raw_local_irq_restore(flags);
}
EXPORT_SYMBOL_GPL(lock_set_class);

void lock_downgrade(struct lockdep_map *lock, unsigned long ip)
{
	unsigned long flags;

	if (unlikely(current->lockdep_recursion))
		return;

	raw_local_irq_save(flags);
	current->lockdep_recursion = 1;
	check_flags(flags);
	if (__lock_downgrade(lock, ip))
		check_chain_key(current);
	current->lockdep_recursion = 0;
	raw_local_irq_restore(flags);
}
EXPORT_SYMBOL_GPL(lock_downgrade);

/*
 * We are not always called with irqs disabled - do that here,
 * and also avoid lockdep recursion:
 */
void lock_acquire(struct lockdep_map *lock, unsigned int subclass,
			  int trylock, int read, int check,
			  struct lockdep_map *nest_lock, unsigned long ip)
{
	unsigned long flags;

	if (unlikely(current->lockdep_recursion))
		return;

	raw_local_irq_save(flags);
	check_flags(flags);

	current->lockdep_recursion = 1;
	trace_lock_acquire(lock, subclass, trylock, read, check, nest_lock, ip);
	__lock_acquire(lock, subclass, trylock, read, check,
		       irqs_disabled_flags(flags), nest_lock, ip, 0, 0);
	current->lockdep_recursion = 0;
	raw_local_irq_restore(flags);
}
EXPORT_SYMBOL_GPL(lock_acquire);

void lock_release(struct lockdep_map *lock, int nested,
			  unsigned long ip)
{
	unsigned long flags;

	if (unlikely(current->lockdep_recursion))
		return;

	raw_local_irq_save(flags);
	check_flags(flags);
	current->lockdep_recursion = 1;
	trace_lock_release(lock, ip);
	if (__lock_release(lock, nested, ip))
		check_chain_key(current);
	current->lockdep_recursion = 0;
	raw_local_irq_restore(flags);
}
EXPORT_SYMBOL_GPL(lock_release);

int lock_is_held_type(struct lockdep_map *lock, int read)
{
	unsigned long flags;
	int ret = 0;

	if (unlikely(current->lockdep_recursion))
		return 1; /* avoid false negative lockdep_assert_held() */

	raw_local_irq_save(flags);
	check_flags(flags);

	current->lockdep_recursion = 1;
	ret = __lock_is_held(lock, read);
	current->lockdep_recursion = 0;
	raw_local_irq_restore(flags);

	return ret;
}
EXPORT_SYMBOL_GPL(lock_is_held_type);

struct pin_cookie lock_pin_lock(struct lockdep_map *lock)
{
	struct pin_cookie cookie = NIL_COOKIE;
	unsigned long flags;

	if (unlikely(current->lockdep_recursion))
		return cookie;

	raw_local_irq_save(flags);
	check_flags(flags);

	current->lockdep_recursion = 1;
	cookie = __lock_pin_lock(lock);
	current->lockdep_recursion = 0;
	raw_local_irq_restore(flags);

	return cookie;
}
EXPORT_SYMBOL_GPL(lock_pin_lock);

void lock_repin_lock(struct lockdep_map *lock, struct pin_cookie cookie)
{
	unsigned long flags;

	if (unlikely(current->lockdep_recursion))
		return;

	raw_local_irq_save(flags);
	check_flags(flags);

	current->lockdep_recursion = 1;
	__lock_repin_lock(lock, cookie);
	current->lockdep_recursion = 0;
	raw_local_irq_restore(flags);
}
EXPORT_SYMBOL_GPL(lock_repin_lock);

void lock_unpin_lock(struct lockdep_map *lock, struct pin_cookie cookie)
{
	unsigned long flags;

	if (unlikely(current->lockdep_recursion))
		return;

	raw_local_irq_save(flags);
	check_flags(flags);

	current->lockdep_recursion = 1;
	__lock_unpin_lock(lock, cookie);
	current->lockdep_recursion = 0;
	raw_local_irq_restore(flags);
}
EXPORT_SYMBOL_GPL(lock_unpin_lock);

void lockdep_set_current_reclaim_state(gfp_t gfp_mask)
{
	current->lockdep_reclaim_gfp = current_gfp_context(gfp_mask);
}
EXPORT_SYMBOL_GPL(lockdep_set_current_reclaim_state);

void lockdep_clear_current_reclaim_state(void)
{
	current->lockdep_reclaim_gfp = 0;
}
EXPORT_SYMBOL_GPL(lockdep_clear_current_reclaim_state);

#ifdef CONFIG_LOCK_STAT
static int
print_lock_contention_bug(struct task_struct *curr, struct lockdep_map *lock,
			   unsigned long ip)
{
	if (!debug_locks_off())
		return 0;
	if (debug_locks_silent)
		return 0;

	printk("\n");
	pr_warn("=================================\n");
	pr_warn("WARNING: bad contention detected!\n");
	print_kernel_ident();
	pr_warn("---------------------------------\n");
	printk("%s/%d is trying to contend lock (",
		curr->comm, task_pid_nr(curr));
	print_lockdep_cache(lock);
	printk(KERN_CONT ") at:\n");
	print_ip_sym(ip);
	printk("but there are no locks held!\n");
	printk("\nother info that might help us debug this:\n");
	lockdep_print_held_locks(curr);

	printk("\nstack backtrace:\n");
	dump_stack();

	return 0;
}

static void
__lock_contended(struct lockdep_map *lock, unsigned long ip)
{
	struct task_struct *curr = current;
	struct held_lock *hlock;
	struct lock_class_stats *stats;
	unsigned int depth;
	int i, contention_point, contending_point;

	depth = curr->lockdep_depth;
	/*
	 * Whee, we contended on this lock, except it seems we're not
	 * actually trying to acquire anything much at all..
	 */
	if (DEBUG_LOCKS_WARN_ON(!depth))
		return;

	hlock = find_held_lock(curr, lock, depth, &i);
	if (!hlock) {
		print_lock_contention_bug(curr, lock, ip);
		return;
	}

	if (hlock->instance != lock)
		return;

	hlock->waittime_stamp = lockstat_clock();

	contention_point = lock_point(hlock_class(hlock)->contention_point, ip);
	contending_point = lock_point(hlock_class(hlock)->contending_point,
				      lock->ip);

	stats = get_lock_stats(hlock_class(hlock));
	if (contention_point < LOCKSTAT_POINTS)
		stats->contention_point[contention_point]++;
	if (contending_point < LOCKSTAT_POINTS)
		stats->contending_point[contending_point]++;
	if (lock->cpu != smp_processor_id())
		stats->bounces[bounce_contended + !!hlock->read]++;
	put_lock_stats(stats);
}

static void
__lock_acquired(struct lockdep_map *lock, unsigned long ip)
{
	struct task_struct *curr = current;
	struct held_lock *hlock;
	struct lock_class_stats *stats;
	unsigned int depth;
	u64 now, waittime = 0;
	int i, cpu;

	depth = curr->lockdep_depth;
	/*
	 * Yay, we acquired ownership of this lock we didn't try to
	 * acquire, how the heck did that happen?
	 */
	if (DEBUG_LOCKS_WARN_ON(!depth))
		return;

	hlock = find_held_lock(curr, lock, depth, &i);
	if (!hlock) {
		print_lock_contention_bug(curr, lock, _RET_IP_);
		return;
	}

	if (hlock->instance != lock)
		return;

	cpu = smp_processor_id();
	if (hlock->waittime_stamp) {
		now = lockstat_clock();
		waittime = now - hlock->waittime_stamp;
		hlock->holdtime_stamp = now;
	}

	trace_lock_acquired(lock, ip);

	stats = get_lock_stats(hlock_class(hlock));
	if (waittime) {
		if (hlock->read)
			lock_time_inc(&stats->read_waittime, waittime);
		else
			lock_time_inc(&stats->write_waittime, waittime);
	}
	if (lock->cpu != cpu)
		stats->bounces[bounce_acquired + !!hlock->read]++;
	put_lock_stats(stats);

	lock->cpu = cpu;
	lock->ip = ip;
}

void lock_contended(struct lockdep_map *lock, unsigned long ip)
{
	unsigned long flags;

	if (unlikely(!lock_stat))
		return;

	if (unlikely(current->lockdep_recursion))
		return;

	raw_local_irq_save(flags);
	check_flags(flags);
	current->lockdep_recursion = 1;
	trace_lock_contended(lock, ip);
	__lock_contended(lock, ip);
	current->lockdep_recursion = 0;
	raw_local_irq_restore(flags);
}
EXPORT_SYMBOL_GPL(lock_contended);

void lock_acquired(struct lockdep_map *lock, unsigned long ip)
{
	unsigned long flags;

	if (unlikely(!lock_stat))
		return;

	if (unlikely(current->lockdep_recursion))
		return;

	raw_local_irq_save(flags);
	check_flags(flags);
	current->lockdep_recursion = 1;
	__lock_acquired(lock, ip);
	current->lockdep_recursion = 0;
	raw_local_irq_restore(flags);
}
EXPORT_SYMBOL_GPL(lock_acquired);
#endif

/*
 * Used by the testsuite, sanitize the validator state
 * after a simulated failure:
 */

void lockdep_reset(void)
{
	unsigned long flags;
	int i;

	raw_local_irq_save(flags);
	current->curr_chain_key = 0;
	current->lockdep_depth = 0;
	current->lockdep_recursion = 0;
	memset(current->held_locks, 0, MAX_LOCK_DEPTH*sizeof(struct held_lock));
	nr_hardirq_chains = 0;
	nr_softirq_chains = 0;
	nr_process_chains = 0;
	debug_locks = 1;
	for (i = 0; i < CHAINHASH_SIZE; i++)
		INIT_HLIST_HEAD(chainhash_table + i);
	raw_local_irq_restore(flags);
}

static void zap_class(struct lock_class *class)
{
	int i;

	/*
	 * Remove all dependencies this lock is
	 * involved in:
	 */
	for (i = 0; i < nr_list_entries; i++) {
		if (list_entries[i].class == class)
			list_del_rcu(&list_entries[i].entry);
	}
	/*
	 * Unhash the class and remove it from the all_lock_classes list:
	 */
	hlist_del_rcu(&class->hash_entry);
	list_del_rcu(&class->lock_entry);

	RCU_INIT_POINTER(class->key, NULL);
	RCU_INIT_POINTER(class->name, NULL);
}

static inline int within(const void *addr, void *start, unsigned long size)
{
	return addr >= start && addr < start + size;
}

/*
 * Used in module.c to remove lock classes from memory that is going to be
 * freed; and possibly re-used by other modules.
 *
 * We will have had one sync_sched() before getting here, so we're guaranteed
 * nobody will look up these exact classes -- they're properly dead but still
 * allocated.
 */
void lockdep_free_key_range(void *start, unsigned long size)
{
	struct lock_class *class;
	struct hlist_head *head;
	unsigned long flags;
	int i;
	int locked;

	raw_local_irq_save(flags);
	locked = graph_lock();

	/*
	 * Unhash all classes that were created by this module:
	 */
	for (i = 0; i < CLASSHASH_SIZE; i++) {
		head = classhash_table + i;
		hlist_for_each_entry_rcu(class, head, hash_entry) {
			if (within(class->key, start, size))
				zap_class(class);
			else if (within(class->name, start, size))
				zap_class(class);
		}
	}

	if (locked)
		graph_unlock();
	raw_local_irq_restore(flags);

	/*
	 * Wait for any possible iterators from look_up_lock_class() to pass
	 * before continuing to free the memory they refer to.
	 *
	 * sync_sched() is sufficient because the read-side is IRQ disable.
	 */
	synchronize_sched();

	/*
	 * XXX at this point we could return the resources to the pool;
	 * instead we leak them. We would need to change to bitmap allocators
	 * instead of the linear allocators we have now.
	 */
}

void lockdep_reset_lock(struct lockdep_map *lock)
{
	struct lock_class *class;
	struct hlist_head *head;
	unsigned long flags;
	int i, j;
	int locked;

	raw_local_irq_save(flags);

	/*
	 * Remove all classes this lock might have:
	 */
	for (j = 0; j < MAX_LOCKDEP_SUBCLASSES; j++) {
		/*
		 * If the class exists we look it up and zap it:
		 */
		class = look_up_lock_class(lock, j);
		if (!IS_ERR_OR_NULL(class))
			zap_class(class);
	}
	/*
	 * Debug check: in the end all mapped classes should
	 * be gone.
	 */
	locked = graph_lock();
	for (i = 0; i < CLASSHASH_SIZE; i++) {
		head = classhash_table + i;
		hlist_for_each_entry_rcu(class, head, hash_entry) {
			int match = 0;

			for (j = 0; j < NR_LOCKDEP_CACHING_CLASSES; j++)
				match |= class == lock->class_cache[j];

			if (unlikely(match)) {
				if (debug_locks_off_graph_unlock()) {
					/*
					 * We all just reset everything, how did it match?
					 */
					WARN_ON(1);
				}
				goto out_restore;
			}
		}
	}
	if (locked)
		graph_unlock();

out_restore:
	raw_local_irq_restore(flags);
}

void __init lockdep_info(void)
{
	printk("Lock dependency validator: Copyright (c) 2006 Red Hat, Inc., Ingo Molnar\n");

	printk("... MAX_LOCKDEP_SUBCLASSES:  %lu\n", MAX_LOCKDEP_SUBCLASSES);
	printk("... MAX_LOCK_DEPTH:          %lu\n", MAX_LOCK_DEPTH);
	printk("... MAX_LOCKDEP_KEYS:        %lu\n", MAX_LOCKDEP_KEYS);
	printk("... CLASSHASH_SIZE:          %lu\n", CLASSHASH_SIZE);
	printk("... MAX_LOCKDEP_ENTRIES:     %lu\n", MAX_LOCKDEP_ENTRIES);
	printk("... MAX_LOCKDEP_CHAINS:      %lu\n", MAX_LOCKDEP_CHAINS);
	printk("... CHAINHASH_SIZE:          %lu\n", CHAINHASH_SIZE);

	printk(" memory used by lock dependency info: %lu kB\n",
		(sizeof(struct lock_class) * MAX_LOCKDEP_KEYS +
		sizeof(struct list_head) * CLASSHASH_SIZE +
		sizeof(struct lock_list) * MAX_LOCKDEP_ENTRIES +
		sizeof(struct lock_chain) * MAX_LOCKDEP_CHAINS +
		sizeof(struct list_head) * CHAINHASH_SIZE
#ifdef CONFIG_PROVE_LOCKING
		+ sizeof(struct circular_queue)
#endif
		) / 1024
		);

	printk(" per task-struct memory footprint: %lu bytes\n",
		sizeof(struct held_lock) * MAX_LOCK_DEPTH);
}

static void
print_freed_lock_bug(struct task_struct *curr, const void *mem_from,
		     const void *mem_to, struct held_lock *hlock)
{
	if (!debug_locks_off())
		return;
	if (debug_locks_silent)
		return;

	printk("\n");
	pr_warn("=========================\n");
	pr_warn("WARNING: held lock freed!\n");
	print_kernel_ident();
	pr_warn("-------------------------\n");
	printk("%s/%d is freeing memory %p-%p, with a lock still held there!\n",
		curr->comm, task_pid_nr(curr), mem_from, mem_to-1);
	print_lock(hlock);
	lockdep_print_held_locks(curr);

	printk("\nstack backtrace:\n");
	dump_stack();
}

static inline int not_in_range(const void* mem_from, unsigned long mem_len,
				const void* lock_from, unsigned long lock_len)
{
	return lock_from + lock_len <= mem_from ||
		mem_from + mem_len <= lock_from;
}

/*
 * Called when kernel memory is freed (or unmapped), or if a lock
 * is destroyed or reinitialized - this code checks whether there is
 * any held lock in the memory range of <from> to <to>:
 */
void debug_check_no_locks_freed(const void *mem_from, unsigned long mem_len)
{
	struct task_struct *curr = current;
	struct held_lock *hlock;
	unsigned long flags;
	int i;

	if (unlikely(!debug_locks))
		return;

	local_irq_save(flags);
	for (i = 0; i < curr->lockdep_depth; i++) {
		hlock = curr->held_locks + i;

		if (not_in_range(mem_from, mem_len, hlock->instance,
					sizeof(*hlock->instance)))
			continue;

		print_freed_lock_bug(curr, mem_from, mem_from + mem_len, hlock);
		break;
	}
	local_irq_restore(flags);
}
EXPORT_SYMBOL_GPL(debug_check_no_locks_freed);

static void print_held_locks_bug(void)
{
	if (!debug_locks_off())
		return;
	if (debug_locks_silent)
		return;

	printk("\n");
	pr_warn("====================================\n");
	pr_warn("WARNING: %s/%d still has locks held!\n",
	       current->comm, task_pid_nr(current));
	print_kernel_ident();
	pr_warn("------------------------------------\n");
	lockdep_print_held_locks(current);
	printk("\nstack backtrace:\n");
	dump_stack();
}

void debug_check_no_locks_held(void)
{
	if (unlikely(current->lockdep_depth > 0))
		print_held_locks_bug();
}
EXPORT_SYMBOL_GPL(debug_check_no_locks_held);

#ifdef __KERNEL__
void debug_show_all_locks(void)
{
	struct task_struct *g, *p;
	int count = 10;
	int unlock = 1;

	if (unlikely(!debug_locks)) {
		printk("INFO: lockdep is turned off.\n");
		return;
	}
	printk("\nShowing all locks held in the system:\n");

	/*
	 * Here we try to get the tasklist_lock as hard as possible,
	 * if not successful after 2 seconds we ignore it (but keep
	 * trying). This is to enable a debug printout even if a
	 * tasklist_lock-holding task deadlocks or crashes.
	 */
retry:
	if (!read_trylock(&tasklist_lock)) {
		if (count == 10)
			printk("hm, tasklist_lock locked, retrying... ");
		if (count) {
			count--;
			printk(" #%d", 10-count);
			mdelay(200);
			goto retry;
		}
		printk(" ignoring it.\n");
		unlock = 0;
	} else {
		if (count != 10)
			printk(KERN_CONT " locked it.\n");
	}

	do_each_thread(g, p) {
		/*
		 * It's not reliable to print a task's held locks
		 * if it's not sleeping (or if it's not the current
		 * task):
		 */
		if (p->state == TASK_RUNNING && p != current)
			continue;
		if (p->lockdep_depth)
			lockdep_print_held_locks(p);
		if (!unlock)
			if (read_trylock(&tasklist_lock))
				unlock = 1;
	} while_each_thread(g, p);

	printk("\n");
	pr_warn("=============================================\n\n");

	if (unlock)
		read_unlock(&tasklist_lock);
}
EXPORT_SYMBOL_GPL(debug_show_all_locks);
#endif

/*
 * Careful: only use this function if you are sure that
 * the task cannot run in parallel!
 */
void debug_show_held_locks(struct task_struct *task)
{
	if (unlikely(!debug_locks)) {
		printk("INFO: lockdep is turned off.\n");
		return;
	}
	lockdep_print_held_locks(task);
}
EXPORT_SYMBOL_GPL(debug_show_held_locks);

asmlinkage __visible void lockdep_sys_exit(void)
{
	struct task_struct *curr = current;

	if (unlikely(curr->lockdep_depth)) {
		if (!debug_locks_off())
			return;
		printk("\n");
		pr_warn("================================================\n");
		pr_warn("WARNING: lock held when returning to user space!\n");
		print_kernel_ident();
		pr_warn("------------------------------------------------\n");
		printk("%s/%d is leaving the kernel with locks still held!\n",
				curr->comm, curr->pid);
		lockdep_print_held_locks(curr);
	}
}

void lockdep_rcu_suspicious(const char *file, const int line, const char *s)
{
	struct task_struct *curr = current;

#ifndef CONFIG_PROVE_RCU_REPEATEDLY
	if (!debug_locks_off())
		return;
#endif /* #ifdef CONFIG_PROVE_RCU_REPEATEDLY */
	/* Note: the following can be executed concurrently, so be careful. */
	printk("\n");
	pr_warn("=============================\n");
	pr_warn("WARNING: suspicious RCU usage\n");
	print_kernel_ident();
	pr_warn("-----------------------------\n");
	printk("%s:%d %s!\n", file, line, s);
	printk("\nother info that might help us debug this:\n\n");
	printk("\n%srcu_scheduler_active = %d, debug_locks = %d\n",
	       !rcu_lockdep_current_cpu_online()
			? "RCU used illegally from offline CPU!\n"
			: !rcu_is_watching()
				? "RCU used illegally from idle CPU!\n"
				: "",
	       rcu_scheduler_active, debug_locks);

	/*
	 * If a CPU is in the RCU-free window in idle (ie: in the section
	 * between rcu_idle_enter() and rcu_idle_exit(), then RCU
	 * considers that CPU to be in an "extended quiescent state",
	 * which means that RCU will be completely ignoring that CPU.
	 * Therefore, rcu_read_lock() and friends have absolutely no
	 * effect on a CPU running in that state. In other words, even if
	 * such an RCU-idle CPU has called rcu_read_lock(), RCU might well
	 * delete data structures out from under it.  RCU really has no
	 * choice here: we need to keep an RCU-free window in idle where
	 * the CPU may possibly enter into low power mode. This way we can
	 * notice an extended quiescent state to other CPUs that started a grace
	 * period. Otherwise we would delay any grace period as long as we run
	 * in the idle task.
	 *
	 * So complain bitterly if someone does call rcu_read_lock(),
	 * rcu_read_lock_bh() and so on from extended quiescent states.
	 */
	if (!rcu_is_watching())
		printk("RCU used illegally from extended quiescent state!\n");

	lockdep_print_held_locks(curr);
	printk("\nstack backtrace:\n");
	dump_stack();
}
EXPORT_SYMBOL_GPL(lockdep_rcu_suspicious);