* [PATCH] mtd: Fix deadlock caused by cancel_work_sync in sm_release
@ 2022-05-24 4:48 ` Duoming Zhou
0 siblings, 0 replies; 6+ messages in thread
From: Duoming Zhou @ 2022-05-24 4:48 UTC (permalink / raw)
To: linux-mtd; +Cc: miquel.raynal, richard, vigneshr, linux-kernel, Duoming Zhou
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>
---
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 0cff2cda1b5..7f955fade83 100644
--- a/drivers/mtd/sm_ftl.c
+++ b/drivers/mtd/sm_ftl.c
@@ -1111,9 +1111,9 @@ 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);
}
--
2.17.1
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH] mtd: Fix deadlock caused by cancel_work_sync in sm_release
@ 2022-05-24 4:48 ` Duoming Zhou
0 siblings, 0 replies; 6+ messages in thread
From: Duoming Zhou @ 2022-05-24 4:48 UTC (permalink / raw)
To: linux-mtd; +Cc: miquel.raynal, richard, vigneshr, linux-kernel, Duoming Zhou
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>
---
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 0cff2cda1b5..7f955fade83 100644
--- a/drivers/mtd/sm_ftl.c
+++ b/drivers/mtd/sm_ftl.c
@@ -1111,9 +1111,9 @@ 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);
}
--
2.17.1
______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH] mtd: Fix deadlock caused by cancel_work_sync in sm_release
2022-05-24 4:48 ` Duoming Zhou
@ 2022-06-09 12:42 ` Miquel Raynal
-1 siblings, 0 replies; 6+ messages in thread
From: Miquel Raynal @ 2022-06-09 12:42 UTC (permalink / raw)
To: Duoming Zhou, linux-mtd; +Cc: Miquel Raynal, richard, vigneshr, linux-kernel
On Tue, 2022-05-24 at 04:48:41 UTC, Duoming Zhou wrote:
> 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>
Applied to https://git.kernel.org/pub/scm/linux/kernel/git/mtd/linux.git mtd/next, thanks.
Miquel
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH] mtd: Fix deadlock caused by cancel_work_sync in sm_release
@ 2022-06-09 12:42 ` Miquel Raynal
0 siblings, 0 replies; 6+ messages in thread
From: Miquel Raynal @ 2022-06-09 12:42 UTC (permalink / raw)
To: Duoming Zhou, linux-mtd; +Cc: Miquel Raynal, richard, vigneshr, linux-kernel
On Tue, 2022-05-24 at 04:48:41 UTC, Duoming Zhou wrote:
> 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>
Applied to https://git.kernel.org/pub/scm/linux/kernel/git/mtd/linux.git mtd/next, thanks.
Miquel
______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH] mtd: Fix deadlock caused by cancel_work_sync in sm_release
@ 2022-05-20 15:04 ` Duoming Zhou
0 siblings, 0 replies; 6+ messages in thread
From: Duoming Zhou @ 2022-05-20 15:04 UTC (permalink / raw)
To: linux-kernel; +Cc: miquel.raynal, richard, vigneshr, linux-mtd, Duoming Zhou
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>
---
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 0cff2cda1b5..7f955fade83 100644
--- a/drivers/mtd/sm_ftl.c
+++ b/drivers/mtd/sm_ftl.c
@@ -1111,9 +1111,9 @@ 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);
}
--
2.17.1
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH] mtd: Fix deadlock caused by cancel_work_sync in sm_release
@ 2022-05-20 15:04 ` Duoming Zhou
0 siblings, 0 replies; 6+ messages in thread
From: Duoming Zhou @ 2022-05-20 15:04 UTC (permalink / raw)
To: linux-kernel; +Cc: miquel.raynal, richard, vigneshr, linux-mtd, Duoming Zhou
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>
---
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 0cff2cda1b5..7f955fade83 100644
--- a/drivers/mtd/sm_ftl.c
+++ b/drivers/mtd/sm_ftl.c
@@ -1111,9 +1111,9 @@ 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);
}
--
2.17.1
______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/
^ permalink raw reply related [flat|nested] 6+ messages in thread
end of thread, other threads:[~2022-06-09 12:43 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
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2022-05-24 4:48 [PATCH] mtd: Fix deadlock caused by cancel_work_sync in sm_release Duoming Zhou
2022-05-24 4:48 ` Duoming Zhou
2022-06-09 12:42 ` Miquel Raynal
2022-06-09 12:42 ` Miquel Raynal
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2022-05-20 15:04 Duoming Zhou
2022-05-20 15:04 ` Duoming Zhou
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