[PATCH 3.9-stable ]drbd: fix for deadlock when using automatic split-brain-recovery

[PATCH 3.9-stable ]drbd: fix for deadlock when using automatic split-brain-recovery

[Jonghwan Choi]

This patch looks like it should be in the 3.9-stable tree, should we apply
it?

------------------

From: "Philipp Reisner <philipp.reisner@linbit.com>"

commit 7c689e63a847316c1b2500f86891b0a574ce7e69 upstream

With an automatic after split-brain recovery policy of
"after-sb-1pri call-pri-lost-after-sb",
when trying to drbd_set_role() to R_SECONDARY,
we run into a deadlock.

This was first recognized and supposedly fixed by
2009-06-10 "Fixed a deadlock when using automatic split brain recovery when
both nodes are"
replacing drbd_set_role() with drbd_change_state() in that code-path,
but the first hunk of that patch forgets to remove the drbd_set_role().

We apparently only ever tested the "two primaries" case.

Cc: <stable@vger.kernel.org> # 3.9.x: ef57f9e6: drbd: Fix build error
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Jonghwan Choi <jhbird.choi@samsung.com>
---
 drivers/block/drbd/drbd_receiver.c |    1 -
 1 file changed, 1 deletion(-)

diff --git a/drivers/block/drbd/drbd_receiver.c
b/drivers/block/drbd/drbd_receiver.c
index a9eccfc..5105f43 100644
--- a/drivers/block/drbd/drbd_receiver.c
+++ b/drivers/block/drbd/drbd_receiver.c
@@ -2661,7 +2661,6 @@ static int drbd_asb_recover_1p(struct drbd_conf *mdev)
__must_hold(local)
 		if (hg == -1 && mdev->state.role == R_PRIMARY) {
 			enum drbd_state_rv rv2;
 
-			drbd_set_role(mdev, R_SECONDARY, 0);
 			 /* drbd_change_state() does not sleep while in
SS_IN_TRANSIENT_STATE,
 			  * we might be here in C_WF_REPORT_PARAMS which is
transient.
 			  * we do not need to wait for the after state
change work either. */
-- 
1.7.9.5

Re: [PATCH 3.9-stable ]drbd: fix for deadlock when using automatic split-brain-recovery

[Philipp Reisner]

Yes, please.

> This patch looks like it should be in the 3.9-stable tree, should we apply
> it?
> 
> ------------------
> 
> From: "Philipp Reisner <philipp.reisner@linbit.com>"
> 
> commit 7c689e63a847316c1b2500f86891b0a574ce7e69 upstream
> 
> With an automatic after split-brain recovery policy of
> "after-sb-1pri call-pri-lost-after-sb",
> when trying to drbd_set_role() to R_SECONDARY,
> we run into a deadlock.
> 
> This was first recognized and supposedly fixed by
> 2009-06-10 "Fixed a deadlock when using automatic split brain recovery when
> both nodes are"
> replacing drbd_set_role() with drbd_change_state() in that code-path,
> but the first hunk of that patch forgets to remove the drbd_set_role().
> 
> We apparently only ever tested the "two primaries" case.
> 
> Cc: <stable@vger.kernel.org> # 3.9.x: ef57f9e6: drbd: Fix build error
> Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
> Signed-off-by: Jens Axboe <axboe@kernel.dk>
> Signed-off-by: Jonghwan Choi <jhbird.choi@samsung.com>
> ---
>  drivers/block/drbd/drbd_receiver.c |    1 -
>  1 file changed, 1 deletion(-)
> 
> diff --git a/drivers/block/drbd/drbd_receiver.c
> b/drivers/block/drbd/drbd_receiver.c
> index a9eccfc..5105f43 100644
> --- a/drivers/block/drbd/drbd_receiver.c
> +++ b/drivers/block/drbd/drbd_receiver.c
> @@ -2661,7 +2661,6 @@ static int drbd_asb_recover_1p(struct drbd_conf *mdev)
> __must_hold(local)
>  		if (hg == -1 && mdev->state.role == R_PRIMARY) {
>  			enum drbd_state_rv rv2;
> 
> -			drbd_set_role(mdev, R_SECONDARY, 0);
>  			 /* drbd_change_state() does not sleep while in
> SS_IN_TRANSIENT_STATE,
>  			  * we might be here in C_WF_REPORT_PARAMS which is
> transient.
>  			  * we do not need to wait for the after state
> change work either. */

Re: [PATCH 3.9-stable ]drbd: fix for deadlock when using automatic split-brain-recovery

[Luis Henriques]

On Thu, May 09, 2013 at 08:14:47AM +0900, Jonghwan Choi wrote:
> This patch looks like it should be in the 3.9-stable tree, should we apply
> it?

This seems to be applicable to older kernels as well (starting with
3.0 at least).

I'm queuing it for 3.5.

Cheers,
--
Luis

> 
> ------------------
> 
> From: "Philipp Reisner <philipp.reisner@linbit.com>"
> 
> commit 7c689e63a847316c1b2500f86891b0a574ce7e69 upstream
> 
> With an automatic after split-brain recovery policy of
> "after-sb-1pri call-pri-lost-after-sb",
> when trying to drbd_set_role() to R_SECONDARY,
> we run into a deadlock.
> 
> This was first recognized and supposedly fixed by
> 2009-06-10 "Fixed a deadlock when using automatic split brain recovery when
> both nodes are"
> replacing drbd_set_role() with drbd_change_state() in that code-path,
> but the first hunk of that patch forgets to remove the drbd_set_role().
> 
> We apparently only ever tested the "two primaries" case.
> 
> Cc: <stable@vger.kernel.org> # 3.9.x: ef57f9e6: drbd: Fix build error
> Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
> Signed-off-by: Jens Axboe <axboe@kernel.dk>
> Signed-off-by: Jonghwan Choi <jhbird.choi@samsung.com>
> ---
>  drivers/block/drbd/drbd_receiver.c |    1 -
>  1 file changed, 1 deletion(-)
> 
> diff --git a/drivers/block/drbd/drbd_receiver.c
> b/drivers/block/drbd/drbd_receiver.c
> index a9eccfc..5105f43 100644
> --- a/drivers/block/drbd/drbd_receiver.c
> +++ b/drivers/block/drbd/drbd_receiver.c
> @@ -2661,7 +2661,6 @@ static int drbd_asb_recover_1p(struct drbd_conf *mdev)
> __must_hold(local)
>  		if (hg == -1 && mdev->state.role == R_PRIMARY) {
>  			enum drbd_state_rv rv2;
>  
> -			drbd_set_role(mdev, R_SECONDARY, 0);
>  			 /* drbd_change_state() does not sleep while in
> SS_IN_TRANSIENT_STATE,
>  			  * we might be here in C_WF_REPORT_PARAMS which is
> transient.
>  			  * we do not need to wait for the after state
> change work either. */
> -- 
> 1.7.9.5
> 
> --
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Re: [PATCH 3.9-stable ]drbd: fix for deadlock when using automatic split-brain-recovery

['Lars Ellenberg']

On Tue, May 14, 2013 at 01:56:55PM +0100, Luis Henriques wrote:
> On Thu, May 09, 2013 at 08:14:47AM +0900, Jonghwan Choi wrote:
> > This patch looks like it should be in the 3.9-stable tree, should we apply
> > it?
> 
> This seems to be applicable to older kernels as well (starting with
> 3.0 at least).

Ack.

> I'm queuing it for 3.5.
> 
> Cheers,
> --
> Luis
> 
> > 
> > ------------------
> > 
> > From: "Philipp Reisner <philipp.reisner@linbit.com>"
> > 
> > commit 7c689e63a847316c1b2500f86891b0a574ce7e69 upstream
> > 
> > With an automatic after split-brain recovery policy of
> > "after-sb-1pri call-pri-lost-after-sb",
> > when trying to drbd_set_role() to R_SECONDARY,
> > we run into a deadlock.
> > 
> > This was first recognized and supposedly fixed by
> > 2009-06-10 "Fixed a deadlock when using automatic split brain recovery when
> > both nodes are"
> > replacing drbd_set_role() with drbd_change_state() in that code-path,
> > but the first hunk of that patch forgets to remove the drbd_set_role().
> > 
> > We apparently only ever tested the "two primaries" case.
> > 
> > Cc: <stable@vger.kernel.org> # 3.9.x: ef57f9e6: drbd: Fix build error
> > Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
> > Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
> > Signed-off-by: Jens Axboe <axboe@kernel.dk>
> > Signed-off-by: Jonghwan Choi <jhbird.choi@samsung.com>
> > ---
> >  drivers/block/drbd/drbd_receiver.c |    1 -
> >  1 file changed, 1 deletion(-)
> > 
> > diff --git a/drivers/block/drbd/drbd_receiver.c
> > b/drivers/block/drbd/drbd_receiver.c
> > index a9eccfc..5105f43 100644
> > --- a/drivers/block/drbd/drbd_receiver.c
> > +++ b/drivers/block/drbd/drbd_receiver.c
> > @@ -2661,7 +2661,6 @@ static int drbd_asb_recover_1p(struct drbd_conf *mdev)
> > __must_hold(local)
> >  		if (hg == -1 && mdev->state.role == R_PRIMARY) {
> >  			enum drbd_state_rv rv2;
> >  
> > -			drbd_set_role(mdev, R_SECONDARY, 0);
> >  			 /* drbd_change_state() does not sleep while in
> > SS_IN_TRANSIENT_STATE,
> >  			  * we might be here in C_WF_REPORT_PARAMS which is
> > transient.
> >  			  * we do not need to wait for the after state
> > change work either. */

Re: [PATCH 3.9-stable ]drbd: fix for deadlock when using automatic split-brain-recovery

[Ben Hutchings]

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On Tue, 2013-05-14 at 15:25 +0200, 'Lars Ellenberg' wrote:
> On Tue, May 14, 2013 at 01:56:55PM +0100, Luis Henriques wrote:
> > On Thu, May 09, 2013 at 08:14:47AM +0900, Jonghwan Choi wrote:
> > > This patch looks like it should be in the 3.9-stable tree, should we apply
> > > it?
> > 
> > This seems to be applicable to older kernels as well (starting with
> > 3.0 at least).
> 
> Ack.
[...]

Queued up for 3.2.  Thanks all.

Ben.

-- 
Ben Hutchings
If at first you don't succeed, you're doing about average.

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