diff options
author | Mikulas Patocka <mpatocka@redhat.com> | 2020-02-19 10:25:45 -0500 |
---|---|---|
committer | Mike Snitzer <snitzer@redhat.com> | 2020-02-27 12:00:52 -0500 |
commit | 7cdf6a0aae1cccf5167f3f04ecddcf648b78e289 (patch) | |
tree | 115172a66547e3074c3c57ada5dd5ac130a98f4d /drivers | |
parent | 7fc2e47f40dd77ab1fcbda6db89614a0173d89c7 (diff) |
dm cache: fix a crash due to incorrect work item cancelling
The crash can be reproduced by running the lvm2 testsuite test
lvconvert-thin-external-cache.sh for several minutes, e.g.:
while :; do make check T=shell/lvconvert-thin-external-cache.sh; done
The crash happens in this call chain:
do_waker -> policy_tick -> smq_tick -> end_hotspot_period -> clear_bitset
-> memset -> __memset -- which accesses an invalid pointer in the vmalloc
area.
The work entry on the workqueue is executed even after the bitmap was
freed. The problem is that cancel_delayed_work doesn't wait for the
running work item to finish, so the work item can continue running and
re-submitting itself even after cache_postsuspend. In order to make sure
that the work item won't be running, we must use cancel_delayed_work_sync.
Also, change flush_workqueue to drain_workqueue, so that if some work item
submits itself or another work item, we are properly waiting for both of
them.
Fixes: c6b4fcbad044 ("dm: add cache target")
Cc: stable@vger.kernel.org # v3.9
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Diffstat (limited to 'drivers')
-rw-r--r-- | drivers/md/dm-cache-target.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/md/dm-cache-target.c b/drivers/md/dm-cache-target.c index 2d32821b3a5b..f4be63671233 100644 --- a/drivers/md/dm-cache-target.c +++ b/drivers/md/dm-cache-target.c @@ -2846,8 +2846,8 @@ static void cache_postsuspend(struct dm_target *ti) prevent_background_work(cache); BUG_ON(atomic_read(&cache->nr_io_migrations)); - cancel_delayed_work(&cache->waker); - flush_workqueue(cache->wq); + cancel_delayed_work_sync(&cache->waker); + drain_workqueue(cache->wq); WARN_ON(cache->tracker.in_flight); /* |