From a452744bcbf706eac65abb4c98496a366820c60a Mon Sep 17 00:00:00 2001 From: Mikulas Patocka Date: Thu, 1 Oct 2015 15:17:43 -0400 Subject: [PATCH] crash in md-raid1 and md-raid10 due to incorrect list manipulation The commit 55ce74d4bfe1b9444436264c637f39a152d1e5ac (md/raid1: ensure device failure recorded before write request returns) is causing crash in the LVM2 testsuite test shell/lvchange-raid.sh. For me the crash is 100% reproducible. The reason for the crash is that the newly added code in raid1d moves the list from conf->bio_end_io_list to tmp, then tests if tmp is non-empty and then incorrectly pops the bio from conf->bio_end_io_list (which is empty because the list was alrady moved). Raid-10 has a similar bug. Kernel Fault: Code=15 regs=000000006ccb8640 (Addr=0000000100000000) CPU: 3 PID: 1930 Comm: mdX_raid1 Not tainted 4.2.0-rc5-bisect+ #35 task: 000000006cc1f258 ti: 000000006ccb8000 task.ti: 000000006ccb8000 YZrvWESTHLNXBCVMcbcbcbcbOGFRQPDI PSW: 00001000000001001111111000001111 Not tainted r00-03 000000ff0804fe0f 000000001059d000 000000001059f818 000000007f16be38 r04-07 000000001059d000 000000007f16be08 0000000000200200 0000000000000001 r08-11 000000006ccb8260 000000007b7934d0 0000000000000001 0000000000000000 r12-15 000000004056f320 0000000000000000 0000000000013dd0 0000000000000000 r16-19 00000000f0d00ae0 0000000000000000 0000000000000000 0000000000000001 r20-23 000000000800000f 0000000042200390 0000000000000000 0000000000000000 r24-27 0000000000000001 000000000800000f 000000007f16be08 000000001059d000 r28-31 0000000100000000 000000006ccb8560 000000006ccb8640 0000000000000000 sr00-03 0000000000249800 0000000000000000 0000000000000000 0000000000249800 sr04-07 0000000000000000 0000000000000000 0000000000000000 0000000000000000 IASQ: 0000000000000000 0000000000000000 IAOQ: 000000001059f61c 000000001059f620 IIR: 0f8010c6 ISR: 0000000000000000 IOR: 0000000100000000 CPU: 3 CR30: 000000006ccb8000 CR31: 0000000000000000 ORIG_R28: 000000001059d000 IAOQ[0]: call_bio_endio+0x34/0x1a8 [raid1] IAOQ[1]: call_bio_endio+0x38/0x1a8 [raid1] RP(r2): raid_end_bio_io+0x88/0x168 [raid1] Backtrace: [<000000001059f818>] raid_end_bio_io+0x88/0x168 [raid1] [<00000000105a4f64>] raid1d+0x144/0x1640 [raid1] [<000000004017fd5c>] kthread+0x144/0x160 Signed-off-by: Mikulas Patocka Fixes: 55ce74d4bfe1 ("md/raid1: ensure device failure recorded before write request returns.") Fixes: 95af587e95aa ("md/raid10: ensure device failure recorded before write request returns.") Signed-off-by: NeilBrown --- drivers/md/raid1.c | 4 ++-- drivers/md/raid10.c | 4 ++-- 2 files changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c index 049df6c4a8cc..ddd8a5f572aa 100644 --- a/drivers/md/raid1.c +++ b/drivers/md/raid1.c @@ -2382,8 +2382,8 @@ static void raid1d(struct md_thread *thread) } spin_unlock_irqrestore(&conf->device_lock, flags); while (!list_empty(&tmp)) { - r1_bio = list_first_entry(&conf->bio_end_io_list, - struct r1bio, retry_list); + r1_bio = list_first_entry(&tmp, struct r1bio, + retry_list); list_del(&r1_bio->retry_list); raid_end_bio_io(r1_bio); } diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c index 7c99a4037715..9f69dc526f8c 100644 --- a/drivers/md/raid10.c +++ b/drivers/md/raid10.c @@ -2688,8 +2688,8 @@ static void raid10d(struct md_thread *thread) } spin_unlock_irqrestore(&conf->device_lock, flags); while (!list_empty(&tmp)) { - r10_bio = list_first_entry(&conf->bio_end_io_list, - struct r10bio, retry_list); + r10_bio = list_first_entry(&tmp, struct r10bio, + retry_list); list_del(&r10_bio->retry_list); raid_end_bio_io(r10_bio); }