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authorMikulas Patocka <mpatocka@redhat.com>2015-12-18 15:19:16 +1100
committerNeilBrown <neilb@suse.com>2015-12-18 15:19:16 +1100
commit0dc10e50f219db3f7fd66d35e5d95860ecde4213 (patch)
treecbff7c61541a7645eb6e0c3a568a96aea6a52679 /drivers/md
parent9b15603dbd98ad1003355ef6ac7d682c75df81c1 (diff)
downloadlinux-0dc10e50f219db3f7fd66d35e5d95860ecde4213.tar.bz2
md: fix bug due to nested suspend
The patch c7bfced9a6716ff66c9d61f934bb60af08d4688c committed to 4.4-rc causes crash in LVM test shell/lvchange-raid.sh. The kernel crashes with this BUG, the reason is that we attempt to suspend a device that is already suspended. See also https://bugzilla.redhat.com/show_bug.cgi?id=1283491 This patch fixes the bug by changing functions mddev_suspend and mddev_resume to always nest. The number of nested calls to mddev_nested_suspend is kept in the variable mddev->suspended. [neilb: made mddev_suspend() always nest instead of introduce mddev_nested_suspend] kernel BUG at drivers/md/md.c:317! CPU: 3 PID: 32754 Comm: lvm Not tainted 4.4.0-rc2 #1 task: 0000000047076040 ti: 0000000047014000 task.ti: 0000000047014000 YZrvWESTHLNXBCVMcbcbcbcbOGFRQPDI PSW: 00001000000001000000000000001111 Not tainted r00-03 000000000804000f 00000000102c5280 0000000010c7522c 000000007e3d1810 r04-07 0000000010c6f000 000000004ef37f20 000000007e3d1dd0 000000007e3d1810 r08-11 000000007c9f1600 0000000000000000 0000000000000001 ffffffffffffffff r12-15 0000000010c1d000 0000000000000041 00000000f98d63c8 00000000f98e49e4 r16-19 00000000f98e49e4 00000000c138fd06 00000000f98d63c8 0000000000000001 r20-23 0000000000000002 000000004ef37f00 00000000000000b0 00000000000001d1 r24-27 00000000424783a0 000000007e3d1dd0 000000007e3d1810 00000000102b2000 r28-31 0000000000000001 0000000047014840 0000000047014930 0000000000000001 sr00-03 0000000007040800 0000000000000000 0000000000000000 0000000007040800 sr04-07 0000000000000000 0000000000000000 0000000000000000 0000000000000000 IASQ: 0000000000000000 0000000000000000 IAOQ: 00000000102c538c 00000000102c5390 IIR: 03ffe01f ISR: 0000000000000000 IOR: 00000000102b2748 CPU: 3 CR30: 0000000047014000 CR31: 0000000000000000 ORIG_R28: 00000000000000b0 IAOQ[0]: mddev_suspend+0x10c/0x160 [md_mod] IAOQ[1]: mddev_suspend+0x110/0x160 [md_mod] RP(r2): raid1_add_disk+0xd4/0x2c0 [raid1] Backtrace: [<0000000010c7522c>] raid1_add_disk+0xd4/0x2c0 [raid1] [<0000000010c20078>] raid_resume+0x390/0x418 [dm_raid] [<00000000105833e8>] dm_table_resume_targets+0xc0/0x188 [dm_mod] [<000000001057f784>] dm_resume+0x144/0x1e0 [dm_mod] [<0000000010587dd4>] dev_suspend+0x1e4/0x568 [dm_mod] [<0000000010589278>] ctl_ioctl+0x1e8/0x428 [dm_mod] [<0000000010589518>] dm_compat_ctl_ioctl+0x18/0x68 [dm_mod] [<0000000040377b88>] compat_SyS_ioctl+0xd0/0x1558 Fixes: c7bfced9a671 ("md: suspend i/o during runtime blk_integrity_unregister") Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: NeilBrown <neilb@suse.com>
Diffstat (limited to 'drivers/md')
-rw-r--r--drivers/md/md.c7
1 files changed, 4 insertions, 3 deletions
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 874c843e72fb..b79b95784e46 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -314,8 +314,8 @@ static blk_qc_t md_make_request(struct request_queue *q, struct bio *bio)
*/
void mddev_suspend(struct mddev *mddev)
{
- BUG_ON(mddev->suspended);
- mddev->suspended = 1;
+ if (mddev->suspended++)
+ return;
synchronize_rcu();
wait_event(mddev->sb_wait, atomic_read(&mddev->active_io) == 0);
mddev->pers->quiesce(mddev, 1);
@@ -326,7 +326,8 @@ EXPORT_SYMBOL_GPL(mddev_suspend);
void mddev_resume(struct mddev *mddev)
{
- mddev->suspended = 0;
+ if (--mddev->suspended)
+ return;
wake_up(&mddev->sb_wait);
mddev->pers->quiesce(mddev, 0);