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[REGRESSION] md: md.c: fix oops in mddev_suspend for raid0

Message ID 1462809042-2974-1-git-send-email-heinzm@redhat.com (mailing list archive)
State Accepted, archived
Delegated to: Mike Snitzer
Headers show

Commit Message

Heinz Mauelshagen May 9, 2016, 3:50 p.m. UTC 
From: Heinz Mauelshagen <heinzm@redhat.com>

Introduced by upstream commit 70d9798b95562abac005d4ba71d28820f9a201eb

The raid0 personality does not create mddev->thread as oposed to
other personalities leading to its unconditional access in
mddev_suspend() causing an oops.

Patch checks for mddev->thread in order to keep the
intention of aforementioned commit.

Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>


---
 drivers/md/md.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Mike Snitzer May 9, 2016, 4:08 p.m. UTC | #1 
On Mon, May 09 2016 at 11:50am -0400,
heinzm@redhat.com <heinzm@redhat.com> wrote:

> From: Heinz Mauelshagen <heinzm@redhat.com>
> 
> Introduced by upstream commit 70d9798b95562abac005d4ba71d28820f9a201eb
> 
> The raid0 personality does not create mddev->thread as oposed to
> other personalities leading to its unconditional access in
> mddev_suspend() causing an oops.
> 
> Patch checks for mddev->thread in order to keep the
> intention of aforementioned commit.
> 
> Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>

Seems this should be marked with:

Fixes: 70d9798b9556 ("MD: warn for potential deadlock")
Cc: stable@vger.kernel.org # 4.5+

> 
> 
> ---
>  drivers/md/md.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/md/md.c b/drivers/md/md.c
> index 194580f..d91920d 100644
> --- a/drivers/md/md.c
> +++ b/drivers/md/md.c
> @@ -305,7 +305,7 @@ static blk_qc_t md_make_request(struct request_queue *q, struct bio *bio)
>   */
>  void mddev_suspend(struct mddev *mddev)
>  {
> -	WARN_ON_ONCE(current == mddev->thread->tsk);
> +	WARN_ON_ONCE(mddev->thread && current == mddev->thread->tsk);
>  	if (mddev->suspended++)
>  		return;
>  	synchronize_rcu();
> -- 
> 2.5.5
> 
> --
> dm-devel mailing list
> dm-devel@redhat.com
> https://www.redhat.com/mailman/listinfo/dm-devel

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diff mbox

Patch

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 194580f..d91920d 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -305,7 +305,7 @@  static blk_qc_t md_make_request(struct request_queue *q, struct bio *bio)
  */
 void mddev_suspend(struct mddev *mddev)
 {
-	WARN_ON_ONCE(current == mddev->thread->tsk);
+	WARN_ON_ONCE(mddev->thread && current == mddev->thread->tsk);
 	if (mddev->suspended++)
 		return;
 	synchronize_rcu();