summaryrefslogtreecommitdiffstats
path: root/kernel/trace/trace_uprobe.c
blob: 9711589273cd58af223a154097687942a6d5e927 (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
// SPDX-License-Identifier: GPL-2.0
/*
 * uprobes-based tracing events
 *
 * Copyright (C) IBM Corporation, 2010-2012
 * Author:	Srikar Dronamraju <srikar@linux.vnet.ibm.com>
 */
#define pr_fmt(fmt)	"trace_uprobe: " fmt

#include <linux/bpf-cgroup.h>
#include <linux/security.h>
#include <linux/ctype.h>
#include <linux/module.h>
#include <linux/uaccess.h>
#include <linux/uprobes.h>
#include <linux/namei.h>
#include <linux/string.h>
#include <linux/rculist.h>

#include "trace_dynevent.h"
#include "trace_probe.h"
#include "trace_probe_tmpl.h"

#define UPROBE_EVENT_SYSTEM	"uprobes"

struct uprobe_trace_entry_head {
	struct trace_entry	ent;
	unsigned long		vaddr[];
};

#define SIZEOF_TRACE_ENTRY(is_return)			\
	(sizeof(struct uprobe_trace_entry_head) +	\
	 sizeof(unsigned long) * (is_return ? 2 : 1))

#define DATAOF_TRACE_ENTRY(entry, is_return)		\
	((void*)(entry) + SIZEOF_TRACE_ENTRY(is_return))

static int trace_uprobe_create(const char *raw_command);
static int trace_uprobe_show(struct seq_file *m, struct dyn_event *ev);
static int trace_uprobe_release(struct dyn_event *ev);
static bool trace_uprobe_is_busy(struct dyn_event *ev);
static bool trace_uprobe_match(const char *system, const char *event,
			int argc, const char **argv, struct dyn_event *ev);

static struct dyn_event_operations trace_uprobe_ops = {
	.create = trace_uprobe_create,
	.show = trace_uprobe_show,
	.is_busy = trace_uprobe_is_busy,
	.free = trace_uprobe_release,
	.match = trace_uprobe_match,
};

/*
 * uprobe event core functions
 */
struct trace_uprobe {
	struct dyn_event		devent;
	struct uprobe_consumer		consumer;
	struct path			path;
	struct inode			*inode;
	char				*filename;
	unsigned long			offset;
	unsigned long			ref_ctr_offset;
	unsigned long			nhit;
	struct trace_probe		tp;
};

static bool is_trace_uprobe(struct dyn_event *ev)
{
	return ev->ops == &trace_uprobe_ops;
}

static struct trace_uprobe *to_trace_uprobe(struct dyn_event *ev)
{
	return container_of(ev, struct trace_uprobe, devent);
}

/**
 * for_each_trace_uprobe - iterate over the trace_uprobe list
 * @pos:	the struct trace_uprobe * for each entry
 * @dpos:	the struct dyn_event * to use as a loop cursor
 */
#define for_each_trace_uprobe(pos, dpos)	\
	for_each_dyn_event(dpos)		\
		if (is_trace_uprobe(dpos) && (pos = to_trace_uprobe(dpos)))

static int register_uprobe_event(struct trace_uprobe *tu);
static int unregister_uprobe_event(struct trace_uprobe *tu);

struct uprobe_dispatch_data {
	struct trace_uprobe	*tu;
	unsigned long		bp_addr;
};

static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs);
static int uretprobe_dispatcher(struct uprobe_consumer *con,
				unsigned long func, struct pt_regs *regs);

#ifdef CONFIG_STACK_GROWSUP
static unsigned long adjust_stack_addr(unsigned long addr, unsigned int n)
{
	return addr - (n * sizeof(long));
}
#else
static unsigned long adjust_stack_addr(unsigned long addr, unsigned int n)
{
	return addr + (n * sizeof(long));
}
#endif

static unsigned long get_user_stack_nth(struct pt_regs *regs, unsigned int n)
{
	unsigned long ret;
	unsigned long addr = user_stack_pointer(regs);

	addr = adjust_stack_addr(addr, n);

	if (copy_from_user(&ret, (void __force __user *) addr, sizeof(ret)))
		return 0;

	return ret;
}

/*
 * Uprobes-specific fetch functions
 */
static nokprobe_inline int
probe_mem_read(void *dest, void *src, size_t size)
{
	void __user *vaddr = (void __force __user *)src;

	return copy_from_user(dest, vaddr, size) ? -EFAULT : 0;
}

static nokprobe_inline int
probe_mem_read_user(void *dest, void *src, size_t size)
{
	return probe_mem_read(dest, src, size);
}

/*
 * Fetch a null-terminated string. Caller MUST set *(u32 *)dest with max
 * length and relative data location.
 */
static nokprobe_inline int
fetch_store_string(unsigned long addr, void *dest, void *base)
{
	long ret;
	u32 loc = *(u32 *)dest;
	int maxlen  = get_loc_len(loc);
	u8 *dst = get_loc_data(dest, base);
	void __user *src = (void __force __user *) addr;

	if (unlikely(!maxlen))
		return -ENOMEM;

	if (addr == FETCH_TOKEN_COMM)
		ret = strlcpy(dst, current->comm, maxlen);
	else
		ret = strncpy_from_user(dst, src, maxlen);
	if (ret >= 0) {
		if (ret == maxlen)
			dst[ret - 1] = '\0';
		else
			/*
			 * Include the terminating null byte. In this case it
			 * was copied by strncpy_from_user but not accounted
			 * for in ret.
			 */
			ret++;
		*(u32 *)dest = make_data_loc(ret, (void *)dst - base);
	}

	return ret;
}

static nokprobe_inline int
fetch_store_string_user(unsigned long addr, void *dest, void *base)
{
	return fetch_store_string(addr, dest, base);
}

/* Return the length of string -- including null terminal byte */
static nokprobe_inline int
fetch_store_strlen(unsigned long addr)
{
	int len;
	void __user *vaddr = (void __force __user *) addr;

	if (addr == FETCH_TOKEN_COMM)
		len = strlen(current->comm) + 1;
	else
		len = strnlen_user(vaddr, MAX_STRING_SIZE);

	return (len > MAX_STRING_SIZE) ? 0 : len;
}

static nokprobe_inline int
fetch_store_strlen_user(unsigned long addr)
{
	return fetch_store_strlen(addr);
}

static unsigned long translate_user_vaddr(unsigned long file_offset)
{
	unsigned long base_addr;
	struct uprobe_dispatch_data *udd;

	udd = (void *) current->utask->vaddr;

	base_addr = udd->bp_addr - udd->tu->offset;
	return base_addr + file_offset;
}

/* Note that we don't verify it, since the code does not come from user space */
static int
process_fetch_insn(struct fetch_insn *code, void *rec, void *dest,
		   void *base)
{
	struct pt_regs *regs = rec;
	unsigned long val;

	/* 1st stage: get value from context */
	switch (code->op) {
	case FETCH_OP_REG:
		val = regs_get_register(regs, code->param);
		break;
	case FETCH_OP_STACK:
		val = get_user_stack_nth(regs, code->param);
		break;
	case FETCH_OP_STACKP:
		val = user_stack_pointer(regs);
		break;
	case FETCH_OP_RETVAL:
		val = regs_return_value(regs);
		break;
	case FETCH_OP_IMM:
		val = code->immediate;
		break;
	case FETCH_OP_COMM:
		val = FETCH_TOKEN_COMM;
		break;
	case FETCH_OP_DATA:
		val = (unsigned long)code->data;
		break;
	case FETCH_OP_FOFFS:
		val = translate_user_vaddr(code->immediate);
		break;
	default:
		return -EILSEQ;
	}
	code++;

	return process_fetch_insn_bottom(code, val, dest, base);
}
NOKPROBE_SYMBOL(process_fetch_insn)

static inline void init_trace_uprobe_filter(struct trace_uprobe_filter *filter)
{
	rwlock_init(&filter->rwlock);
	filter->nr_systemwide = 0;
	INIT_LIST_HEAD(&filter->perf_events);
}

static inline bool uprobe_filter_is_empty(struct trace_uprobe_filter *filter)
{
	return !filter->nr_systemwide && list_empty(&filter->perf_events);
}

static inline bool is_ret_probe(struct trace_uprobe *tu)
{
	return tu->consumer.ret_handler != NULL;
}

static bool trace_uprobe_is_busy(struct dyn_event *ev)
{
	struct trace_uprobe *tu = to_trace_uprobe(ev);

	return trace_probe_is_enabled(&tu->tp);
}

static bool trace_uprobe_match_command_head(struct trace_uprobe *tu,
					    int argc, const char **argv)
{
	char buf[MAX_ARGSTR_LEN + 1];
	int len;

	if (!argc)
		return true;

	len = strlen(tu->filename);
	if (strncmp(tu->filename, argv[0], len) || argv[0][len] != ':')
		return false;

	if (tu->ref_ctr_offset == 0)
		snprintf(buf, sizeof(buf), "0x%0*lx",
				(int)(sizeof(void *) * 2), tu->offset);
	else
		snprintf(buf, sizeof(buf), "0x%0*lx(0x%lx)",
				(int)(sizeof(void *) * 2), tu->offset,
				tu->ref_ctr_offset);
	if (strcmp(buf, &argv[0][len + 1]))
		return false;

	argc--; argv++;

	return trace_probe_match_command_args(&tu->tp, argc, argv);
}

static bool trace_uprobe_match(const char *system, const char *event,
			int argc, const char **argv, struct dyn_event *ev)
{
	struct trace_uprobe *tu = to_trace_uprobe(ev);

	return strcmp(trace_probe_name(&tu->tp), event) == 0 &&
	   (!system || strcmp(trace_probe_group_name(&tu->tp), system) == 0) &&
	   trace_uprobe_match_command_head(tu, argc, argv);
}

static nokprobe_inline struct trace_uprobe *
trace_uprobe_primary_from_call(struct trace_event_call *call)
{
	struct trace_probe *tp;

	tp = trace_probe_primary_from_call(call);
	if (WARN_ON_ONCE(!tp))
		return NULL;

	return container_of(tp, struct trace_uprobe, tp);
}

/*
 * Allocate new trace_uprobe and initialize it (including uprobes).
 */
static struct trace_uprobe *
alloc_trace_uprobe(const char *group, const char *event, int nargs, bool is_ret)
{
	struct trace_uprobe *tu;
	int ret;

	tu = kzalloc(struct_size(tu, tp.args, nargs), GFP_KERNEL);
	if (!tu)
		return ERR_PTR(-ENOMEM);

	ret = trace_probe_init(&tu->tp, event, group, true);
	if (ret < 0)
		goto error;

	dyn_event_init(&tu->devent, &trace_uprobe_ops);
	tu->consumer.handler = uprobe_dispatcher;
	if (is_ret)
		tu->consumer.ret_handler = uretprobe_dispatcher;
	init_trace_uprobe_filter(tu->tp.event->filter);
	return tu;

error:
	kfree(tu);

	return ERR_PTR(ret);
}

static void free_trace_uprobe(struct trace_uprobe *tu)
{
	if (!tu)
		return;

	path_put(&tu->path);
	trace_probe_cleanup(&tu->tp);
	kfree(tu->filename);
	kfree(tu);
}

static struct trace_uprobe *find_probe_event(const char *event, const char *group)
{
	struct dyn_event *pos;
	struct trace_uprobe *tu;

	for_each_trace_uprobe(tu, pos)
		if (strcmp(trace_probe_name(&tu->tp), event) == 0 &&
		    strcmp(trace_probe_group_name(&tu->tp), group) == 0)
			return tu;

	return NULL;
}

/* Unregister a trace_uprobe and probe_event */
static int unregister_trace_uprobe(struct trace_uprobe *tu)
{
	int ret;

	if (trace_probe_has_sibling(&tu->tp))
		goto unreg;

	/* If there's a reference to the dynamic event */
	if (trace_event_dyn_busy(trace_probe_event_call(&tu->tp)))
		return -EBUSY;

	ret = unregister_uprobe_event(tu);
	if (ret)
		return ret;

unreg:
	dyn_event_remove(&tu->devent);
	trace_probe_unlink(&tu->tp);
	free_trace_uprobe(tu);
	return 0;
}

static bool trace_uprobe_has_same_uprobe(struct trace_uprobe *orig,
					 struct trace_uprobe *comp)
{
	struct trace_probe_event *tpe = orig->tp.event;
	struct inode *comp_inode = d_real_inode(comp->path.dentry);
	int i;

	list_for_each_entry(orig, &tpe->probes, tp.list) {
		if (comp_inode != d_real_inode(orig->path.dentry) ||
		    comp->offset != orig->offset)
			continue;

		/*
		 * trace_probe_compare_arg_type() ensured that nr_args and
		 * each argument name and type are same. Let's compare comm.
		 */
		for (i = 0; i < orig->tp.nr_args; i++) {
			if (strcmp(orig->tp.args[i].comm,
				   comp->tp.args[i].comm))
				break;
		}

		if (i == orig->tp.nr_args)
			return true;
	}

	return false;
}

static int append_trace_uprobe(struct trace_uprobe *tu, struct trace_uprobe *to)
{
	int ret;

	ret = trace_probe_compare_arg_type(&tu->tp, &to->tp);
	if (ret) {
		/* Note that argument starts index = 2 */
		trace_probe_log_set_index(ret + 1);
		trace_probe_log_err(0, DIFF_ARG_TYPE);
		return -EEXIST;
	}
	if (trace_uprobe_has_same_uprobe(to, tu)) {
		trace_probe_log_set_index(0);
		trace_probe_log_err(0, SAME_PROBE);
		return -EEXIST;
	}

	/* Append to existing event */
	ret = trace_probe_append(&tu->tp, &to->tp);
	if (!ret)
		dyn_event_add(&tu->devent, trace_probe_event_call(&tu->tp));

	return ret;
}

/*
 * Uprobe with multiple reference counter is not allowed. i.e.
 * If inode and offset matches, reference counter offset *must*
 * match as well. Though, there is one exception: If user is
 * replacing old trace_uprobe with new one(same group/event),
 * then we allow same uprobe with new reference counter as far
 * as the new one does not conflict with any other existing
 * ones.
 */
static int validate_ref_ctr_offset(struct trace_uprobe *new)
{
	struct dyn_event *pos;
	struct trace_uprobe *tmp;
	struct inode *new_inode = d_real_inode(new->path.dentry);

	for_each_trace_uprobe(tmp, pos) {
		if (new_inode == d_real_inode(tmp->path.dentry) &&
		    new->offset == tmp->offset &&
		    new->ref_ctr_offset != tmp->ref_ctr_offset) {
			pr_warn("Reference counter offset mismatch.");
			return -EINVAL;
		}
	}
	return 0;
}

/* Register a trace_uprobe and probe_event */
static int register_trace_uprobe(struct trace_uprobe *tu)
{
	struct trace_uprobe *old_tu;
	int ret;

	mutex_lock(&event_mutex);

	ret = validate_ref_ctr_offset(tu);
	if (ret)
		goto end;

	/* register as an event */
	old_tu = find_probe_event(trace_probe_name(&tu->tp),
				  trace_probe_group_name(&tu->tp));
	if (old_tu) {
		if (is_ret_probe(tu) != is_ret_probe(old_tu)) {
			trace_probe_log_set_index(0);
			trace_probe_log_err(0, DIFF_PROBE_TYPE);
			ret = -EEXIST;
		} else {
			ret = append_trace_uprobe(tu, old_tu);
		}
		goto end;
	}

	ret = register_uprobe_event(tu);
	if (ret) {
		if (ret == -EEXIST) {
			trace_probe_log_set_index(0);
			trace_probe_log_err(0, EVENT_EXIST);
		} else
			pr_warn("Failed to register probe event(%d)\n", ret);
		goto end;
	}

	dyn_event_add(&tu->devent, trace_probe_event_call(&tu->tp));

end:
	mutex_unlock(&event_mutex);

	return ret;
}

/*
 * Argument syntax:
 *  - Add uprobe: p|r[:[GRP/]EVENT] PATH:OFFSET[%return][(REF)] [FETCHARGS]
 */
static int __trace_uprobe_create(int argc, const char **argv)
{
	struct trace_uprobe *tu;
	const char *event = NULL, *group = UPROBE_EVENT_SYSTEM;
	char *arg, *filename, *rctr, *rctr_end, *tmp;
	char buf[MAX_EVENT_NAME_LEN];
	enum probe_print_type ptype;
	struct path path;
	unsigned long offset, ref_ctr_offset;
	bool is_return = false;
	int i, ret;

	ret = 0;
	ref_ctr_offset = 0;

	switch (argv[0][0]) {
	case 'r':
		is_return = true;
		break;
	case 'p':
		break;
	default:
		return -ECANCELED;
	}

	if (argc < 2)
		return -ECANCELED;

	if (argv[0][1] == ':')
		event = &argv[0][2];

	if (!strchr(argv[1], '/'))
		return -ECANCELED;

	filename = kstrdup(argv[1], GFP_KERNEL);
	if (!filename)
		return -ENOMEM;

	/* Find the last occurrence, in case the path contains ':' too. */
	arg = strrchr(filename, ':');
	if (!arg || !isdigit(arg[1])) {
		kfree(filename);
		return -ECANCELED;
	}

	trace_probe_log_init("trace_uprobe", argc, argv);
	trace_probe_log_set_index(1);	/* filename is the 2nd argument */

	*arg++ = '\0';
	ret = kern_path(filename, LOOKUP_FOLLOW, &path);
	if (ret) {
		trace_probe_log_err(0, FILE_NOT_FOUND);
		kfree(filename);
		trace_probe_log_clear();
		return ret;
	}
	if (!d_is_reg(path.dentry)) {
		trace_probe_log_err(0, NO_REGULAR_FILE);
		ret = -EINVAL;
		goto fail_address_parse;
	}

	/* Parse reference counter offset if specified. */
	rctr = strchr(arg, '(');
	if (rctr) {
		rctr_end = strchr(rctr, ')');
		if (!rctr_end) {
			ret = -EINVAL;
			rctr_end = rctr + strlen(rctr);
			trace_probe_log_err(rctr_end - filename,
					    REFCNT_OPEN_BRACE);
			goto fail_address_parse;
		} else if (rctr_end[1] != '\0') {
			ret = -EINVAL;
			trace_probe_log_err(rctr_end + 1 - filename,
					    BAD_REFCNT_SUFFIX);
			goto fail_address_parse;
		}

		*rctr++ = '\0';
		*rctr_end = '\0';
		ret = kstrtoul(rctr, 0, &ref_ctr_offset);
		if (ret) {
			trace_probe_log_err(rctr - filename, BAD_REFCNT);
			goto fail_address_parse;
		}
	}

	/* Check if there is %return suffix */
	tmp = strchr(arg, '%');
	if (tmp) {
		if (!strcmp(tmp, "%return")) {
			*tmp = '\0';
			is_return = true;
		} else {
			trace_probe_log_err(tmp - filename, BAD_ADDR_SUFFIX);
			ret = -EINVAL;
			goto fail_address_parse;
		}
	}

	/* Parse uprobe offset. */
	ret = kstrtoul(arg, 0, &offset);
	if (ret) {
		trace_probe_log_err(arg - filename, BAD_UPROBE_OFFS);
		goto fail_address_parse;
	}

	/* setup a probe */
	trace_probe_log_set_index(0);
	if (event) {
		ret = traceprobe_parse_event_name(&event, &group, buf,
						  event - argv[0]);
		if (ret)
			goto fail_address_parse;
	} else {
		char *tail;
		char *ptr;

		tail = kstrdup(kbasename(filename), GFP_KERNEL);
		if (!tail) {
			ret = -ENOMEM;
			goto fail_address_parse;
		}

		ptr = strpbrk(tail, ".-_");
		if (ptr)
			*ptr = '\0';

		snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_0x%lx", 'p', tail, offset);
		event = buf;
		kfree(tail);
	}

	argc -= 2;
	argv += 2;

	tu = alloc_trace_uprobe(group, event, argc, is_return);
	if (IS_ERR(tu)) {
		ret = PTR_ERR(tu);
		/* This must return -ENOMEM otherwise there is a bug */
		WARN_ON_ONCE(ret != -ENOMEM);
		goto fail_address_parse;
	}
	tu->offset = offset;
	tu->ref_ctr_offset = ref_ctr_offset;
	tu->path = path;
	tu->filename = filename;

	/* parse arguments */
	for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
		trace_probe_log_set_index(i + 2);
		ret = traceprobe_parse_probe_arg(&tu->tp, i, argv[i],
					is_return ? TPARG_FL_RETURN : 0);
		if (ret)
			goto error;
	}

	ptype = is_ret_probe(tu) ? PROBE_PRINT_RETURN : PROBE_PRINT_NORMAL;
	ret = traceprobe_set_print_fmt(&tu->tp, ptype);
	if (ret < 0)
		goto error;

	ret = register_trace_uprobe(tu);
	if (!ret)
		goto out;

error:
	free_trace_uprobe(tu);
out:
	trace_probe_log_clear();
	return ret;

fail_address_parse:
	trace_probe_log_clear();
	path_put(&path);
	kfree(filename);

	return ret;
}

int trace_uprobe_create(const char *raw_command)
{
	return trace_probe_create(raw_command, __trace_uprobe_create);
}

static int create_or_delete_trace_uprobe(const char *raw_command)
{
	int ret;

	if (raw_command[0] == '-')
		return dyn_event_release(raw_command, &trace_uprobe_ops);

	ret = trace_uprobe_create(raw_command);
	return ret == -ECANCELED ? -EINVAL : ret;
}

static int trace_uprobe_release(struct dyn_event *ev)
{
	struct trace_uprobe *tu = to_trace_uprobe(ev);

	return unregister_trace_uprobe(tu);
}

/* Probes listing interfaces */
static int trace_uprobe_show(struct seq_file *m, struct dyn_event *ev)
{
	struct trace_uprobe *tu = to_trace_uprobe(ev);
	char c = is_ret_probe(tu) ? 'r' : 'p';
	int i;

	seq_printf(m, "%c:%s/%s %s:0x%0*lx", c, trace_probe_group_name(&tu->tp),
			trace_probe_name(&tu->tp), tu->filename,
			(int)(sizeof(void *) * 2), tu->offset);

	if (tu->ref_ctr_offset)
		seq_printf(m, "(0x%lx)", tu->ref_ctr_offset);

	for (i = 0; i < tu->tp.nr_args; i++)
		seq_printf(m, " %s=%s", tu->tp.args[i].name, tu->tp.args[i].comm);

	seq_putc(m, '\n');
	return 0;
}

static int probes_seq_show(struct seq_file *m, void *v)
{
	struct dyn_event *ev = v;

	if (!is_trace_uprobe(ev))
		return 0;

	return trace_uprobe_show(m, ev);
}

static const struct seq_operations probes_seq_op = {
	.start  = dyn_event_seq_start,
	.next   = dyn_event_seq_next,
	.stop   = dyn_event_seq_stop,
	.show   = probes_seq_show
};

static int probes_open(struct inode *inode, struct file *file)
{
	int ret;

	ret = security_locked_down(LOCKDOWN_TRACEFS);
	if (ret)
		return ret;

	if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
		ret = dyn_events_release_all(&trace_uprobe_ops);
		if (ret)
			return ret;
	}

	return seq_open(file, &probes_seq_op);
}

static ssize_t probes_write(struct file *file, const char __user *buffer,
			    size_t count, loff_t *ppos)
{
	return trace_parse_run_command(file, buffer, count, ppos,
					create_or_delete_trace_uprobe);
}

static const struct file_operations uprobe_events_ops = {
	.owner		= THIS_MODULE,
	.open		= probes_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= seq_release,
	.write		= probes_write,
};

/* Probes profiling interfaces */
static int probes_profile_seq_show(struct seq_file *m, void *v)
{
	struct dyn_event *ev = v;
	struct trace_uprobe *tu;

	if (!is_trace_uprobe(ev))
		return 0;

	tu = to_trace_uprobe(ev);
	seq_printf(m, "  %s %-44s %15lu\n", tu->filename,
			trace_probe_name(&tu->tp), tu->nhit);
	return 0;
}

static const struct seq_operations profile_seq_op = {
	.start  = dyn_event_seq_start,
	.next   = dyn_event_seq_next,
	.stop   = dyn_event_seq_stop,
	.show	= probes_profile_seq_show
};

static int profile_open(struct inode *inode, struct file *file)
{
	int ret;

	ret = security_locked_down(LOCKDOWN_TRACEFS);
	if (ret)
		return ret;

	return seq_open(file, &profile_seq_op);
}

static const struct file_operations uprobe_profile_ops = {
	.owner		= THIS_MODULE,
	.open		= profile_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= seq_release,
};

struct uprobe_cpu_buffer {
	struct mutex mutex;
	void *buf;
};
static struct uprobe_cpu_buffer __percpu *uprobe_cpu_buffer;
static int uprobe_buffer_refcnt;

static int uprobe_buffer_init(void)
{
	int cpu, err_cpu;

	uprobe_cpu_buffer = alloc_percpu(struct uprobe_cpu_buffer);
	if (uprobe_cpu_buffer == NULL)
		return -ENOMEM;

	for_each_possible_cpu(cpu) {
		struct page *p = alloc_pages_node(cpu_to_node(cpu),
						  GFP_KERNEL, 0);
		if (p == NULL) {
			err_cpu = cpu;
			goto err;
		}
		per_cpu_ptr(uprobe_cpu_buffer, cpu)->buf = page_address(p);
		mutex_init(&per_cpu_ptr(uprobe_cpu_buffer, cpu)->mutex);
	}

	return 0;

err:
	for_each_possible_cpu(cpu) {
		if (cpu == err_cpu)
			break;
		free_page((unsigned long)per_cpu_ptr(uprobe_cpu_buffer, cpu)->buf);
	}

	free_percpu(uprobe_cpu_buffer);
	return -ENOMEM;
}

static int uprobe_buffer_enable(void)
{
	int ret = 0;

	BUG_ON(!mutex_is_locked(&event_mutex));

	if (uprobe_buffer_refcnt++ == 0) {
		ret = uprobe_buffer_init();
		if (ret < 0)
			uprobe_buffer_refcnt--;
	}

	return ret;
}

static void uprobe_buffer_disable(void)
{
	int cpu;

	BUG_ON(!mutex_is_locked(&event_mutex));

	if (--uprobe_buffer_refcnt == 0) {
		for_each_possible_cpu(cpu)
			free_page((unsigned long)per_cpu_ptr(uprobe_cpu_buffer,
							     cpu)->buf);

		free_percpu(uprobe_cpu_buffer);
		uprobe_cpu_buffer = NULL;
	}
}

static struct uprobe_cpu_buffer *uprobe_buffer_get(void)
{
	struct uprobe_cpu_buffer *ucb;
	int cpu;

	cpu = raw_smp_processor_id();
	ucb = per_cpu_ptr(uprobe_cpu_buffer, cpu);

	/*
	 * Use per-cpu buffers for fastest access, but we might migrate
	 * so the mutex makes sure we have sole access to it.
	 */
	mutex_lock(&ucb->mutex);

	return ucb;
}

static void uprobe_buffer_put(struct uprobe_cpu_buffer *ucb)
{
	mutex_unlock(&ucb->mutex);
}

static void __uprobe_trace_func(struct trace_uprobe *tu,
				unsigned long func, struct pt_regs *regs,
				struct uprobe_cpu_buffer *ucb, int dsize,
				struct trace_event_file *trace_file)
{
	struct uprobe_trace_entry_head *entry;
	struct trace_event_buffer fbuffer;
	void *data;
	int size, esize;
	struct trace_event_call *call = trace_probe_event_call(&tu->tp);

	WARN_ON(call != trace_file->event_call);

	if (WARN_ON_ONCE(tu->tp.size + dsize > PAGE_SIZE))
		return;

	if (trace_trigger_soft_disabled(trace_file))
		return;

	esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
	size = esize + tu->tp.size + dsize;
	entry = trace_event_buffer_reserve(&fbuffer, trace_file, size);
	if (!entry)
		return;

	if (is_ret_probe(tu)) {
		entry->vaddr[0] = func;
		entry->vaddr[1] = instruction_pointer(regs);
		data = DATAOF_TRACE_ENTRY(entry, true);
	} else {
		entry->vaddr[0] = instruction_pointer(regs);
		data = DATAOF_TRACE_ENTRY(entry, false);
	}

	memcpy(data, ucb->buf, tu->tp.size + dsize);

	trace_event_buffer_commit(&fbuffer);
}

/* uprobe handler */
static int uprobe_trace_func(struct trace_uprobe *tu, struct pt_regs *regs,
			     struct uprobe_cpu_buffer *ucb, int dsize)
{
	struct event_file_link *link;

	if (is_ret_probe(tu))
		return 0;

	rcu_read_lock();
	trace_probe_for_each_link_rcu(link, &tu->tp)
		__uprobe_trace_func(tu, 0, regs, ucb, dsize, link->file);
	rcu_read_unlock();

	return 0;
}

static void uretprobe_trace_func(struct trace_uprobe *tu, unsigned long func,
				 struct pt_regs *regs,
				 struct uprobe_cpu_buffer *ucb, int dsize)
{
	struct event_file_link *link;

	rcu_read_lock();
	trace_probe_for_each_link_rcu(link, &tu->tp)
		__uprobe_trace_func(tu, func, regs, ucb, dsize, link->file);
	rcu_read_unlock();
}

/* Event entry printers */
static enum print_line_t
print_uprobe_event(struct trace_iterator *iter, int flags, struct trace_event *event)
{
	struct uprobe_trace_entry_head *entry;
	struct trace_seq *s = &iter->seq;
	struct trace_uprobe *tu;
	u8 *data;

	entry = (struct uprobe_trace_entry_head *)iter->ent;
	tu = trace_uprobe_primary_from_call(
		container_of(event, struct trace_event_call, event));
	if (unlikely(!tu))
		goto out;

	if (is_ret_probe(tu)) {
		trace_seq_printf(s, "%s: (0x%lx <- 0x%lx)",
				 trace_probe_name(&tu->tp),
				 entry->vaddr[1], entry->vaddr[0]);
		data = DATAOF_TRACE_ENTRY(entry, true);
	} else {
		trace_seq_printf(s, "%s: (0x%lx)",
				 trace_probe_name(&tu->tp),
				 entry->vaddr[0]);
		data = DATAOF_TRACE_ENTRY(entry, false);
	}

	if (print_probe_args(s, tu->tp.args, tu->tp.nr_args, data, entry) < 0)
		goto out;

	trace_seq_putc(s, '\n');

 out:
	return trace_handle_return(s);
}

typedef bool (*filter_func_t)(struct uprobe_consumer *self,
				enum uprobe_filter_ctx ctx,
				struct mm_struct *mm);

static int trace_uprobe_enable(struct trace_uprobe *tu, filter_func_t filter)
{
	int ret;

	tu->consumer.filter = filter;
	tu->inode = d_real_inode(tu->path.dentry);

	if (tu->ref_ctr_offset)
		ret = uprobe_register_refctr(tu->inode, tu->offset,
				tu->ref_ctr_offset, &tu->consumer);
	else
		ret = uprobe_register(tu->inode, tu->offset, &tu->consumer);

	if (ret)
		tu->inode = NULL;

	return ret;
}

static void __probe_event_disable(struct trace_probe *tp)
{
	struct trace_uprobe *tu;

	tu = container_of(tp, struct trace_uprobe, tp);
	WARN_ON(!uprobe_filter_is_empty(tu->tp.event->filter));

	list_for_each_entry(tu, trace_probe_probe_list(tp), tp.list) {
		if (!tu->inode)
			continue;

		uprobe_unregister(tu->inode, tu->offset, &tu->consumer);
		tu->inode = NULL;
	}
}

static int probe_event_enable(struct trace_event_call *call,
			struct trace_event_file *file, filter_func_t filter)
{
	struct trace_probe *tp;
	struct trace_uprobe *tu;
	bool enabled;
	int ret;

	tp = trace_probe_primary_from_call(call);
	if (WARN_ON_ONCE(!tp))
		return -ENODEV;
	enabled = trace_probe_is_enabled(tp);

	/* This may also change "enabled" state */
	if (file) {
		if (trace_probe_test_flag(tp, TP_FLAG_PROFILE))
			return -EINTR;

		ret = trace_probe_add_file(tp, file);
		if (ret < 0)
			return ret;
	} else {
		if (trace_probe_test_flag(tp, TP_FLAG_TRACE))
			return -EINTR;

		trace_probe_set_flag(tp, TP_FLAG_PROFILE);
	}

	tu = container_of(tp, struct trace_uprobe, tp);
	WARN_ON(!uprobe_filter_is_empty(tu->tp.event->filter));

	if (enabled)
		return 0;

	ret = uprobe_buffer_enable();
	if (ret)
		goto err_flags;

	list_for_each_entry(tu, trace_probe_probe_list(tp), tp.list) {
		ret = trace_uprobe_enable(tu, filter);
		if (ret) {
			__probe_event_disable(tp);
			goto err_buffer;
		}
	}

	return 0;

 err_buffer:
	uprobe_buffer_disable();

 err_flags:
	if (file)
		trace_probe_remove_file(tp, file);
	else
		trace_probe_clear_flag(tp, TP_FLAG_PROFILE);

	return ret;
}

static void probe_event_disable(struct trace_event_call *call,
				struct trace_event_file *file)
{
	struct trace_probe *tp;

	tp = trace_probe_primary_from_call(call);
	if (WARN_ON_ONCE(!tp))
		return;

	if (!trace_probe_is_enabled(tp))
		return;

	if (file) {
		if (trace_probe_remove_file(tp, file) < 0)
			return;

		if (trace_probe_is_enabled(tp))
			return;
	} else
		trace_probe_clear_flag(tp, TP_FLAG_PROFILE);

	__probe_event_disable(tp);
	uprobe_buffer_disable();
}

static int uprobe_event_define_fields(struct trace_event_call *event_call)
{
	int ret, size;
	struct uprobe_trace_entry_head field;
	struct trace_uprobe *tu;

	tu = trace_uprobe_primary_from_call(event_call);
	if (unlikely(!tu))
		return -ENODEV;

	if (is_ret_probe(tu)) {
		DEFINE_FIELD(unsigned long, vaddr[0], FIELD_STRING_FUNC, 0);
		DEFINE_FIELD(unsigned long, vaddr[1], FIELD_STRING_RETIP, 0);
		size = SIZEOF_TRACE_ENTRY(true);
	} else {
		DEFINE_FIELD(unsigned long, vaddr[0], FIELD_STRING_IP, 0);
		size = SIZEOF_TRACE_ENTRY(false);
	}

	return traceprobe_define_arg_fields(event_call, size, &tu->tp);
}

#ifdef CONFIG_PERF_EVENTS
static bool
__uprobe_perf_filter(struct trace_uprobe_filter *filter, struct mm_struct *mm)
{
	struct perf_event *event;

	if (filter->nr_systemwide)
		return true;

	list_for_each_entry(event, &filter->perf_events, hw.tp_list) {
		if (event->hw.target->mm == mm)
			return true;
	}

	return false;
}

static inline bool
trace_uprobe_filter_event(struct trace_uprobe_filter *filter,
			  struct perf_event *event)
{
	return __uprobe_perf_filter(filter, event->hw.target->mm);
}

static bool trace_uprobe_filter_remove(struct trace_uprobe_filter *filter,
				       struct perf_event *event)
{
	bool done;

	write_lock(&filter->rwlock);
	if (event->hw.target) {
		list_del(&event->hw.tp_list);
		done = filter->nr_systemwide ||
			(event->hw.target->flags & PF_EXITING) ||
			trace_uprobe_filter_event(filter, event);
	} else {
		filter->nr_systemwide--;
		done = filter->nr_systemwide;
	}
	write_unlock(&filter->rwlock);

	return done;
}

/* This returns true if the filter always covers target mm */
static bool trace_uprobe_filter_add(struct trace_uprobe_filter *filter,
				    struct perf_event *event)
{
	bool done;

	write_lock(&filter->rwlock);
	if (event->hw.target) {
		/*
		 * event->parent != NULL means copy_process(), we can avoid
		 * uprobe_apply(). current->mm must be probed and we can rely
		 * on dup_mmap() which preserves the already installed bp's.
		 *
		 * attr.enable_on_exec means that exec/mmap will install the
		 * breakpoints we need.
		 */
		done = filter->nr_systemwide ||
			event->parent || event->attr.enable_on_exec ||
			trace_uprobe_filter_event(filter, event);
		list_add(&event->hw.tp_list, &filter->perf_events);
	} else {
		done = filter->nr_systemwide;
		filter->nr_systemwide++;
	}
	write_unlock(&filter->rwlock);

	return done;
}

static int uprobe_perf_close(struct trace_event_call *call,
			     struct perf_event *event)
{
	struct trace_probe *tp;
	struct trace_uprobe *tu;
	int ret = 0;

	tp = trace_probe_primary_from_call(call);
	if (WARN_ON_ONCE(!tp))
		return -ENODEV;

	tu = container_of(tp, struct trace_uprobe, tp);
	if (trace_uprobe_filter_remove(tu->tp.event->filter, event))
		return 0;

	list_for_each_entry(tu, trace_probe_probe_list(tp), tp.list) {
		ret = uprobe_apply(tu->inode, tu->offset, &tu->consumer, false);
		if (ret)
			break;
	}

	return ret;
}

static int uprobe_perf_open(struct trace_event_call *call,
			    struct perf_event *event)
{
	struct trace_probe *tp;
	struct trace_uprobe *tu;
	int err = 0;

	tp = trace_probe_primary_from_call(call);
	if (WARN_ON_ONCE(!tp))
		return -ENODEV;

	tu = container_of(tp, struct trace_uprobe, tp);
	if (trace_uprobe_filter_add(tu->tp.event->filter, event))
		return 0;

	list_for_each_entry(tu, trace_probe_probe_list(tp), tp.list) {
		err = uprobe_apply(tu->inode, tu->offset, &tu->consumer, true);
		if (err) {
			uprobe_perf_close(call, event);
			break;
		}
	}

	return err;
}

static bool uprobe_perf_filter(struct uprobe_consumer *uc,
				enum uprobe_filter_ctx ctx, struct mm_struct *mm)
{
	struct trace_uprobe_filter *filter;
	struct trace_uprobe *tu;
	int ret;

	tu = container_of(uc, struct trace_uprobe, consumer);
	filter = tu->tp.event->filter;

	read_lock(&filter->rwlock);
	ret = __uprobe_perf_filter(filter, mm);
	read_unlock(&filter->rwlock);

	return ret;
}

static void __uprobe_perf_func(struct trace_uprobe *tu,
			       unsigned long func, struct pt_regs *regs,
			       struct uprobe_cpu_buffer *ucb, int dsize)
{
	struct trace_event_call *call = trace_probe_event_call(&tu->tp);
	struct uprobe_trace_entry_head *entry;
	struct hlist_head *head;
	void *data;
	int size, esize;
	int rctx;

	if (bpf_prog_array_valid(call)) {
		u32 ret;

		preempt_disable();
		ret = trace_call_bpf(call, regs);
		preempt_enable();
		if (!ret)
			return;
	}

	esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));

	size = esize + tu->tp.size + dsize;
	size = ALIGN(size + sizeof(u32), sizeof(u64)) - sizeof(u32);
	if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE, "profile buffer not large enough"))
		return;

	preempt_disable();
	head = this_cpu_ptr(call->perf_events);
	if (hlist_empty(head))
		goto out;

	entry = perf_trace_buf_alloc(size, NULL, &rctx);
	if (!entry)
		goto out;

	if (is_ret_probe(tu)) {
		entry->vaddr[0] = func;
		entry->vaddr[1] = instruction_pointer(regs);
		data = DATAOF_TRACE_ENTRY(entry, true);
	} else {
		entry->vaddr[0] = instruction_pointer(regs);
		data = DATAOF_TRACE_ENTRY(entry, false);
	}

	memcpy(data, ucb->buf, tu->tp.size + dsize);

	if (size - esize > tu->tp.size + dsize) {
		int len = tu->tp.size + dsize;

		memset(data + len, 0, size - esize - len);
	}

	perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
			      head, NULL);
 out:
	preempt_enable();
}

/* uprobe profile handler */
static int uprobe_perf_func(struct trace_uprobe *tu, struct pt_regs *regs,
			    struct uprobe_cpu_buffer *ucb, int dsize)
{
	if (!uprobe_perf_filter(&tu->consumer, 0, current->mm))
		return UPROBE_HANDLER_REMOVE;

	if (!is_ret_probe(tu))
		__uprobe_perf_func(tu, 0, regs, ucb, dsize);
	return 0;
}

static void uretprobe_perf_func(struct trace_uprobe *tu, unsigned long func,
				struct pt_regs *regs,
				struct uprobe_cpu_buffer *ucb, int dsize)
{
	__uprobe_perf_func(tu, func, regs, ucb, dsize);
}

int bpf_get_uprobe_info(const struct perf_event *event, u32 *fd_type,
			const char **filename, u64 *probe_offset,
			bool perf_type_tracepoint)
{
	const char *pevent = trace_event_name(event->tp_event);
	const char *group = event->tp_event->class->system;
	struct trace_uprobe *tu;

	if (perf_type_tracepoint)
		tu = find_probe_event(pevent, group);
	else
		tu = trace_uprobe_primary_from_call(event->tp_event);
	if (!tu)
		return -EINVAL;

	*fd_type = is_ret_probe(tu) ? BPF_FD_TYPE_URETPROBE
				    : BPF_FD_TYPE_UPROBE;
	*filename = tu->filename;
	*probe_offset = tu->offset;
	return 0;
}
#endif	/* CONFIG_PERF_EVENTS */

static int
trace_uprobe_register(struct trace_event_call *event, enum trace_reg type,
		      void *data)
{
	struct trace_event_file *file = data;

	switch (type) {
	case TRACE_REG_REGISTER:
		return probe_event_enable(event, file, NULL);

	case TRACE_REG_UNREGISTER:
		probe_event_disable(event, file);
		return 0;

#ifdef CONFIG_PERF_EVENTS
	case TRACE_REG_PERF_REGISTER:
		return probe_event_enable(event, NULL, uprobe_perf_filter);

	case TRACE_REG_PERF_UNREGISTER:
		probe_event_disable(event, NULL);
		return 0;

	case TRACE_REG_PERF_OPEN:
		return uprobe_perf_open(event, data);

	case TRACE_REG_PERF_CLOSE:
		return uprobe_perf_close(event, data);

#endif
	default:
		return 0;
	}
}

static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs)
{
	struct trace_uprobe *tu;
	struct uprobe_dispatch_data udd;
	struct uprobe_cpu_buffer *ucb;
	int dsize, esize;
	int ret = 0;


	tu = container_of(con, struct trace_uprobe, consumer);
	tu->nhit++;

	udd.tu = tu;
	udd.bp_addr = instruction_pointer(regs);

	current->utask->vaddr = (unsigned long) &udd;

	if (WARN_ON_ONCE(!uprobe_cpu_buffer))
		return 0;

	dsize = __get_data_size(&tu->tp, regs);
	esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));

	ucb = uprobe_buffer_get();
	store_trace_args(ucb->buf, &tu->tp, regs, esize, dsize);

	if (trace_probe_test_flag(&tu->tp, TP_FLAG_TRACE))
		ret |= uprobe_trace_func(tu, regs, ucb, dsize);

#ifdef CONFIG_PERF_EVENTS
	if (trace_probe_test_flag(&tu->tp, TP_FLAG_PROFILE))
		ret |= uprobe_perf_func(tu, regs, ucb, dsize);
#endif
	uprobe_buffer_put(ucb);
	return ret;
}

static int uretprobe_dispatcher(struct uprobe_consumer *con,
				unsigned long func, struct pt_regs *regs)
{
	struct trace_uprobe *tu;
	struct uprobe_dispatch_data udd;
	struct uprobe_cpu_buffer *ucb;
	int dsize, esize;

	tu = container_of(con, struct trace_uprobe, consumer);

	udd.tu = tu;
	udd.bp_addr = func;

	current->utask->vaddr = (unsigned long) &udd;

	if (WARN_ON_ONCE(!uprobe_cpu_buffer))
		return 0;

	dsize = __get_data_size(&tu->tp, regs);
	esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));

	ucb = uprobe_buffer_get();
	store_trace_args(ucb->buf, &tu->tp, regs, esize, dsize);

	if (trace_probe_test_flag(&tu->tp, TP_FLAG_TRACE))
		uretprobe_trace_func(tu, func, regs, ucb, dsize);

#ifdef CONFIG_PERF_EVENTS
	if (trace_probe_test_flag(&tu->tp, TP_FLAG_PROFILE))
		uretprobe_perf_func(tu, func, regs, ucb, dsize);
#endif
	uprobe_buffer_put(ucb);
	return 0;
}

static struct trace_event_functions uprobe_funcs = {
	.trace		= print_uprobe_event
};

static struct trace_event_fields uprobe_fields_array[] = {
	{ .type = TRACE_FUNCTION_TYPE,
	  .define_fields = uprobe_event_define_fields },
	{}
};

static inline void init_trace_event_call(struct trace_uprobe *tu)
{
	struct trace_event_call *call = trace_probe_event_call(&tu->tp);
	call->event.funcs = &uprobe_funcs;
	call->class->fields_array = uprobe_fields_array;

	call->flags = TRACE_EVENT_FL_UPROBE | TRACE_EVENT_FL_CAP_ANY;
	call->class->reg = trace_uprobe_register;
}

static int register_uprobe_event(struct trace_uprobe *tu)
{
	init_trace_event_call(tu);

	return trace_probe_register_event_call(&tu->tp);
}

static int unregister_uprobe_event(struct trace_uprobe *tu)
{
	return trace_probe_unregister_event_call(&tu->tp);
}

#ifdef CONFIG_PERF_EVENTS
struct trace_event_call *
create_local_trace_uprobe(char *name, unsigned long offs,
			  unsigned long ref_ctr_offset, bool is_return)
{
	enum probe_print_type ptype;
	struct trace_uprobe *tu;
	struct path path;
	int ret;

	ret = kern_path(name, LOOKUP_FOLLOW, &path);
	if (ret)
		return ERR_PTR(ret);

	if (!d_is_reg(path.dentry)) {
		path_put(&path);
		return ERR_PTR(-EINVAL);
	}

	/*
	 * local trace_kprobes are not added to dyn_event, so they are never
	 * searched in find_trace_kprobe(). Therefore, there is no concern of
	 * duplicated name "DUMMY_EVENT" here.
	 */
	tu = alloc_trace_uprobe(UPROBE_EVENT_SYSTEM, "DUMMY_EVENT", 0,
				is_return);

	if (IS_ERR(tu)) {
		pr_info("Failed to allocate trace_uprobe.(%d)\n",
			(int)PTR_ERR(tu));
		path_put(&path);
		return ERR_CAST(tu);
	}

	tu->offset = offs;
	tu->path = path;
	tu->ref_ctr_offset = ref_ctr_offset;
	tu->filename = kstrdup(name, GFP_KERNEL);
	if (!tu->filename) {
		ret = -ENOMEM;
		goto error;
	}

	init_trace_event_call(tu);

	ptype = is_ret_probe(tu) ? PROBE_PRINT_RETURN : PROBE_PRINT_NORMAL;
	if (traceprobe_set_print_fmt(&tu->tp, ptype) < 0) {
		ret = -ENOMEM;
		goto error;
	}

	return trace_probe_event_call(&tu->tp);
error:
	free_trace_uprobe(tu);
	return ERR_PTR(ret);
}

void destroy_local_trace_uprobe(struct trace_event_call *event_call)
{
	struct trace_uprobe *tu;

	tu = trace_uprobe_primary_from_call(event_call);

	free_trace_uprobe(tu);
}
#endif /* CONFIG_PERF_EVENTS */

/* Make a trace interface for controlling probe points */
static __init int init_uprobe_trace(void)
{
	int ret;

	ret = dyn_event_register(&trace_uprobe_ops);
	if (ret)
		return ret;

	ret = tracing_init_dentry();
	if (ret)
		return 0;

	trace_create_file("uprobe_events", TRACE_MODE_WRITE, NULL,
				    NULL, &uprobe_events_ops);
	/* Profile interface */
	trace_create_file("uprobe_profile", TRACE_MODE_READ, NULL,
				    NULL, &uprobe_profile_ops);
	return 0;
}

fs_initcall(init_uprobe_trace);