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author | Mikulas Patocka <mpatocka@redhat.com> | 2020-02-19 10:25:45 -0500 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-03-11 07:53:14 +0100 |
commit | 4afa0856f0c94c6b6cd5d8c5e8554e460e5a9f75 (patch) | |
tree | aa6925da61b3cb4ea47a55cf240d7de79a9b3ea7 /crypto | |
parent | 728802730843fe2d76a45767564bad987e9cd3ec (diff) |
dm cache: fix a crash due to incorrect work item cancelling
commit 7cdf6a0aae1cccf5167f3f04ecddcf648b78e289 upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'crypto')
0 files changed, 0 insertions, 0 deletions