mtd: sm_ftl: Fix deadlock caused by cancel_work_sync in sm_release
[ Upstream commit a61528d997619a518ee8c51cf0ef0513021afaff ]
There is a deadlock between sm_release and sm_cache_flush_work
which is a work item. The cancel_work_sync in sm_release will
not return until sm_cache_flush_work is finished. If we hold
mutex_lock and use cancel_work_sync to wait the work item to
finish, the work item also requires mutex_lock. As a result,
the sm_release will be blocked forever. The race condition is
shown below:
(Thread 1) | (Thread 2)
sm_release |
mutex_lock(&ftl->mutex) | sm_cache_flush_work
| mutex_lock(&ftl->mutex)
cancel_work_sync | ...
This patch moves del_timer_sync and cancel_work_sync out of
mutex_lock in order to mitigate deadlock.
Fixes: 7d17c02a01
("mtd: Add new SmartMedia/xD FTL")
Signed-off-by: Duoming Zhou <duoming@zju.edu.cn>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20220524044841.10517-1-duoming@zju.edu.cn
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
parent
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@ -1091,9 +1091,9 @@ static void sm_release(struct mtd_blktrans_dev *dev)
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{
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struct sm_ftl *ftl = dev->priv;
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mutex_lock(&ftl->mutex);
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del_timer_sync(&ftl->timer);
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cancel_work_sync(&ftl->flush_work);
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mutex_lock(&ftl->mutex);
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sm_cache_flush(ftl);
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mutex_unlock(&ftl->mutex);
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}
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