From: Duoming Zhou <duoming@zju.edu.cn> stable inclusion from stable-v5.10.137 commit b4e150d295ba5234f5e4b3731ddbcb1651b7547f category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I60PLB Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- [ 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: 7d17c02a01a1 ("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> Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com> Reviewed-by: Wei Li <liwei391@huawei.com> --- drivers/mtd/sm_ftl.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/mtd/sm_ftl.c b/drivers/mtd/sm_ftl.c index b9f272408c4d..2fedae67c07c 100644 --- a/drivers/mtd/sm_ftl.c +++ b/drivers/mtd/sm_ftl.c @@ -1098,9 +1098,9 @@ static void sm_release(struct mtd_blktrans_dev *dev) { struct sm_ftl *ftl = dev->priv; - mutex_lock(&ftl->mutex); del_timer_sync(&ftl->timer); cancel_work_sync(&ftl->flush_work); + mutex_lock(&ftl->mutex); sm_cache_flush(ftl); mutex_unlock(&ftl->mutex); } -- 2.20.1