diff options
| author | Roman Gushchin <klamm@yandex-team.ru> | 2015-10-31 10:53:50 +1100 |
|---|---|---|
| committer | NeilBrown <neilb@suse.com> | 2015-10-31 10:53:50 +1100 |
| commit | b8a9d66d043ffac116100775a469f05f5158c16f (patch) | |
| tree | 919820a8816f109a663b940b7074bb1b6fb58b6a | |
| parent | 8bce6d35b308d73cdb2ee273c95d711a55be688c (diff) | |
| download | linux-b8a9d66d043ffac116100775a469f05f5158c16f.tar.bz2 | |
md/raid5: fix locking in handle_stripe_clean_event()
After commit 566c09c53455 ("raid5: relieve lock contention in get_active_stripe()")
__find_stripe() is called under conf->hash_locks + hash.
But handle_stripe_clean_event() calls remove_hash() under
conf->device_lock.
Under some cirscumstances the hash chain can be circuited,
and we get an infinite loop with disabled interrupts and locked hash
lock in __find_stripe(). This leads to hard lockup on multiple CPUs
and following system crash.
I was able to reproduce this behavior on raid6 over 6 ssd disks.
The devices_handle_discard_safely option should be set to enable trim
support. The following script was used:
for i in `seq 1 32`; do
dd if=/dev/zero of=large$i bs=10M count=100 &
done
neilb: original was against a 3.x kernel. I forward-ported
to 4.3-rc. This verison is suitable for any kernel since
Commit: 59fc630b8b5f ("RAID5: batch adjacent full stripe write")
(v4.1+). I'll post a version for earlier kernels to stable.
Signed-off-by: Roman Gushchin <klamm@yandex-team.ru>
Fixes: 566c09c53455 ("raid5: relieve lock contention in get_active_stripe()")
Signed-off-by: NeilBrown <neilb@suse.com>
Cc: Shaohua Li <shli@kernel.org>
Cc: <stable@vger.kernel.org> # 3.13 - 4.2
| -rw-r--r-- | drivers/md/raid5.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index 49bb8d3ff9be..45933c160697 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -3499,6 +3499,7 @@ returnbi: } if (!discard_pending && test_bit(R5_Discard, &sh->dev[sh->pd_idx].flags)) { + int hash; clear_bit(R5_Discard, &sh->dev[sh->pd_idx].flags); clear_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags); if (sh->qd_idx >= 0) { @@ -3512,16 +3513,17 @@ returnbi: * no updated data, so remove it from hash list and the stripe * will be reinitialized */ - spin_lock_irq(&conf->device_lock); unhash: + hash = sh->hash_lock_index; + spin_lock_irq(conf->hash_locks + hash); remove_hash(sh); + spin_unlock_irq(conf->hash_locks + hash); if (head_sh->batch_head) { sh = list_first_entry(&sh->batch_list, struct stripe_head, batch_list); if (sh != head_sh) goto unhash; } - spin_unlock_irq(&conf->device_lock); sh = head_sh; if (test_bit(STRIPE_SYNC_REQUESTED, &sh->state)) |