2022-07-01 09:07:58

by Dmitry Osipenko

Subject: [PATCH v8 1/2] drm/gem: Properly annotate WW context on drm_gem_lock_reservations() error

Use ww_acquire_fini() in the error code paths. Otherwise lockdep
thinks that lock is held when lock's memory is freed after the
drm_gem_lock_reservations() error. The ww_acquire_context needs to be
annotated as "released", which fixes the noisy "WARNING: held lock freed!"
splat of VirtIO-GPU driver with CONFIG_DEBUG_MUTEXES=y and enabled lockdep.

Cc: [email protected]
Fixes: 7edc3e3b975b5 ("drm: Add helpers for locking an array of BO reservations.")
Reviewed-by: Thomas Hellström <[email protected]>
Signed-off-by: Dmitry Osipenko <[email protected]>
---
drivers/gpu/drm/drm_gem.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c
index eb0c2d041f13..86d670c71286 100644
--- a/drivers/gpu/drm/drm_gem.c
+++ b/drivers/gpu/drm/drm_gem.c
@@ -1226,7 +1226,7 @@ drm_gem_lock_reservations(struct drm_gem_object **objs, int count,
ret = dma_resv_lock_slow_interruptible(obj->resv,
acquire_ctx);
if (ret) {
- ww_acquire_done(acquire_ctx);
+ ww_acquire_fini(acquire_ctx);
return ret;
}
}
@@ -1251,7 +1251,7 @@ drm_gem_lock_reservations(struct drm_gem_object **objs, int count,
goto retry;
}

- ww_acquire_done(acquire_ctx);
+ ww_acquire_fini(acquire_ctx);
return ret;
}
}
--
2.36.1

2022-07-05 11:47:24

by Christian König

Subject: Re: [PATCH v8 1/2] drm/gem: Properly annotate WW context on drm_gem_lock_reservations() error

Am 01.07.22 um 11:02 schrieb Dmitry Osipenko:
> Use ww_acquire_fini() in the error code paths. Otherwise lockdep
> thinks that lock is held when lock's memory is freed after the
> drm_gem_lock_reservations() error. The ww_acquire_context needs to be
> annotated as "released", which fixes the noisy "WARNING: held lock freed!"
> splat of VirtIO-GPU driver with CONFIG_DEBUG_MUTEXES=y and enabled lockdep.
>
> Cc: [email protected]
> Fixes: 7edc3e3b975b5 ("drm: Add helpers for locking an array of BO reservations.")
> Reviewed-by: Thomas Hellström <[email protected]>
> Signed-off-by: Dmitry Osipenko <[email protected]>

Reviewed-by: Christian König <[email protected]>

> ---
> drivers/gpu/drm/drm_gem.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c
> index eb0c2d041f13..86d670c71286 100644
> --- a/drivers/gpu/drm/drm_gem.c
> +++ b/drivers/gpu/drm/drm_gem.c
> @@ -1226,7 +1226,7 @@ drm_gem_lock_reservations(struct drm_gem_object **objs, int count,
> ret = dma_resv_lock_slow_interruptible(obj->resv,
> acquire_ctx);
> if (ret) {
> - ww_acquire_done(acquire_ctx);
> + ww_acquire_fini(acquire_ctx);
> return ret;
> }
> }
> @@ -1251,7 +1251,7 @@ drm_gem_lock_reservations(struct drm_gem_object **objs, int count,
> goto retry;
> }
>
> - ww_acquire_done(acquire_ctx);
> + ww_acquire_fini(acquire_ctx);
> return ret;
> }
> }

2022-08-09 16:54:29

by Daniel Vetter

Subject: Re: [PATCH v8 1/2] drm/gem: Properly annotate WW context on drm_gem_lock_reservations() error

On Tue, Jul 05, 2022 at 01:33:51PM +0200, Christian K?nig wrote:
> Am 01.07.22 um 11:02 schrieb Dmitry Osipenko:
> > Use ww_acquire_fini() in the error code paths. Otherwise lockdep
> > thinks that lock is held when lock's memory is freed after the
> > drm_gem_lock_reservations() error. The ww_acquire_context needs to be
> > annotated as "released", which fixes the noisy "WARNING: held lock freed!"
> > splat of VirtIO-GPU driver with CONFIG_DEBUG_MUTEXES=y and enabled lockdep.
> >
> > Cc: [email protected]
> > Fixes: 7edc3e3b975b5 ("drm: Add helpers for locking an array of BO reservations.")
> > Reviewed-by: Thomas Hellstr?m <[email protected]>
> > Signed-off-by: Dmitry Osipenko <[email protected]>
>
> Reviewed-by: Christian K?nig <[email protected]>

Also added this r-b tag when merging to drm-misc-next-fixes.
-Daniel

>
> > ---
> > drivers/gpu/drm/drm_gem.c | 4 ++--
> > 1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c
> > index eb0c2d041f13..86d670c71286 100644
> > --- a/drivers/gpu/drm/drm_gem.c
> > +++ b/drivers/gpu/drm/drm_gem.c
> > @@ -1226,7 +1226,7 @@ drm_gem_lock_reservations(struct drm_gem_object **objs, int count,
> > ret = dma_resv_lock_slow_interruptible(obj->resv,
> > acquire_ctx);
> > if (ret) {
> > - ww_acquire_done(acquire_ctx);
> > + ww_acquire_fini(acquire_ctx);
> > return ret;
> > }
> > }
> > @@ -1251,7 +1251,7 @@ drm_gem_lock_reservations(struct drm_gem_object **objs, int count,
> > goto retry;
> > }
> > - ww_acquire_done(acquire_ctx);
> > + ww_acquire_fini(acquire_ctx);
> > return ret;
> > }
> > }
>

--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch

2022-08-10 07:39:08

by Christian König

Subject: Re: [PATCH v8 1/2] drm/gem: Properly annotate WW context on drm_gem_lock_reservations() error

Am 09.08.22 um 18:44 schrieb Daniel Vetter:
> On Tue, Jul 05, 2022 at 01:33:51PM +0200, Christian König wrote:
>> Am 01.07.22 um 11:02 schrieb Dmitry Osipenko:
>>> Use ww_acquire_fini() in the error code paths. Otherwise lockdep
>>> thinks that lock is held when lock's memory is freed after the
>>> drm_gem_lock_reservations() error. The ww_acquire_context needs to be
>>> annotated as "released", which fixes the noisy "WARNING: held lock freed!"
>>> splat of VirtIO-GPU driver with CONFIG_DEBUG_MUTEXES=y and enabled lockdep.
>>>
>>> Cc: [email protected]
>>> Fixes: 7edc3e3b975b5 ("drm: Add helpers for locking an array of BO reservations.")
>>> Reviewed-by: Thomas Hellström <[email protected]>
>>> Signed-off-by: Dmitry Osipenko <[email protected]>
>> Reviewed-by: Christian König <[email protected]>
> Also added this r-b tag when merging to drm-misc-next-fixes.

IIRC I've already pushed this to drm-misc-fixes with a CC stable tag
about 2 weeks ago.

Please double check, it probably just hasn't come down the stream again yet.

Christian.

> -Daniel
>
>>> ---
>>> drivers/gpu/drm/drm_gem.c | 4 ++--
>>> 1 file changed, 2 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c
>>> index eb0c2d041f13..86d670c71286 100644
>>> --- a/drivers/gpu/drm/drm_gem.c
>>> +++ b/drivers/gpu/drm/drm_gem.c
>>> @@ -1226,7 +1226,7 @@ drm_gem_lock_reservations(struct drm_gem_object **objs, int count,
>>> ret = dma_resv_lock_slow_interruptible(obj->resv,
>>> acquire_ctx);
>>> if (ret) {
>>> - ww_acquire_done(acquire_ctx);
>>> + ww_acquire_fini(acquire_ctx);
>>> return ret;
>>> }
>>> }
>>> @@ -1251,7 +1251,7 @@ drm_gem_lock_reservations(struct drm_gem_object **objs, int count,
>>> goto retry;
>>> }
>>> - ww_acquire_done(acquire_ctx);
>>> + ww_acquire_fini(acquire_ctx);
>>> return ret;
>>> }
>>> }

2022-08-10 09:18:48

by Daniel Vetter

Subject: Re: [PATCH v8 1/2] drm/gem: Properly annotate WW context on drm_gem_lock_reservations() error

On Wed, 10 Aug 2022 at 08:52, Christian König <[email protected]> wrote:
>
> Am 09.08.22 um 18:44 schrieb Daniel Vetter:
> > On Tue, Jul 05, 2022 at 01:33:51PM +0200, Christian König wrote:
> >> Am 01.07.22 um 11:02 schrieb Dmitry Osipenko:
> >>> Use ww_acquire_fini() in the error code paths. Otherwise lockdep
> >>> thinks that lock is held when lock's memory is freed after the
> >>> drm_gem_lock_reservations() error. The ww_acquire_context needs to be
> >>> annotated as "released", which fixes the noisy "WARNING: held lock freed!"
> >>> splat of VirtIO-GPU driver with CONFIG_DEBUG_MUTEXES=y and enabled lockdep.
> >>>
> >>> Cc: [email protected]
> >>> Fixes: 7edc3e3b975b5 ("drm: Add helpers for locking an array of BO reservations.")
> >>> Reviewed-by: Thomas Hellström <[email protected]>
> >>> Signed-off-by: Dmitry Osipenko <[email protected]>
> >> Reviewed-by: Christian König <[email protected]>
> > Also added this r-b tag when merging to drm-misc-next-fixes.
>
> IIRC I've already pushed this to drm-misc-fixes with a CC stable tag
> about 2 weeks ago.
>
> Please double check, it probably just hasn't come down the stream again yet.

Hm quickly check and I didn't spot it? There's a few patches from
Dmitry in the last few pulls, and some more stuff pending, but not
these two afaics?
-Daniel

>
> Christian.
>
> > -Daniel
> >
> >>> ---
> >>> drivers/gpu/drm/drm_gem.c | 4 ++--
> >>> 1 file changed, 2 insertions(+), 2 deletions(-)
> >>>
> >>> diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c
> >>> index eb0c2d041f13..86d670c71286 100644
> >>> --- a/drivers/gpu/drm/drm_gem.c
> >>> +++ b/drivers/gpu/drm/drm_gem.c
> >>> @@ -1226,7 +1226,7 @@ drm_gem_lock_reservations(struct drm_gem_object **objs, int count,
> >>> ret = dma_resv_lock_slow_interruptible(obj->resv,
> >>> acquire_ctx);
> >>> if (ret) {
> >>> - ww_acquire_done(acquire_ctx);
> >>> + ww_acquire_fini(acquire_ctx);
> >>> return ret;
> >>> }
> >>> }
> >>> @@ -1251,7 +1251,7 @@ drm_gem_lock_reservations(struct drm_gem_object **objs, int count,
> >>> goto retry;
> >>> }
> >>> - ww_acquire_done(acquire_ctx);
> >>> + ww_acquire_fini(acquire_ctx);
> >>> return ret;
> >>> }
> >>> }
>


--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch

2022-08-10 09:19:16

by Christian König

Subject: Re: [PATCH v8 1/2] drm/gem: Properly annotate WW context on drm_gem_lock_reservations() error

Am 10.08.22 um 10:33 schrieb Daniel Vetter:
> On Wed, 10 Aug 2022 at 08:52, Christian König <[email protected]> wrote:
>> Am 09.08.22 um 18:44 schrieb Daniel Vetter:
>>> On Tue, Jul 05, 2022 at 01:33:51PM +0200, Christian König wrote:
>>>> Am 01.07.22 um 11:02 schrieb Dmitry Osipenko:
>>>>> Use ww_acquire_fini() in the error code paths. Otherwise lockdep
>>>>> thinks that lock is held when lock's memory is freed after the
>>>>> drm_gem_lock_reservations() error. The ww_acquire_context needs to be
>>>>> annotated as "released", which fixes the noisy "WARNING: held lock freed!"
>>>>> splat of VirtIO-GPU driver with CONFIG_DEBUG_MUTEXES=y and enabled lockdep.
>>>>>
>>>>> Cc: [email protected]
>>>>> Fixes: 7edc3e3b975b5 ("drm: Add helpers for locking an array of BO reservations.")
>>>>> Reviewed-by: Thomas Hellström <[email protected]>
>>>>> Signed-off-by: Dmitry Osipenko <[email protected]>
>>>> Reviewed-by: Christian König <[email protected]>
>>> Also added this r-b tag when merging to drm-misc-next-fixes.
>> IIRC I've already pushed this to drm-misc-fixes with a CC stable tag
>> about 2 weeks ago.
>>
>> Please double check, it probably just hasn't come down the stream again yet.
> Hm quickly check and I didn't spot it? There's a few patches from
> Dmitry in the last few pulls, and some more stuff pending, but not
> these two afaics?

Mhm, there is some potential that I wanted to push it but got distracted
by the re-occurring drm-tip build breakages.

Anyway what I wanted to say is that this stuff should probably go to
drm-misc-fixes with a CC: stable tag :)

Christian.

> -Daniel
>
>> Christian.
>>
>>> -Daniel
>>>
>>>>> ---
>>>>> drivers/gpu/drm/drm_gem.c | 4 ++--
>>>>> 1 file changed, 2 insertions(+), 2 deletions(-)
>>>>>
>>>>> diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c
>>>>> index eb0c2d041f13..86d670c71286 100644
>>>>> --- a/drivers/gpu/drm/drm_gem.c
>>>>> +++ b/drivers/gpu/drm/drm_gem.c
>>>>> @@ -1226,7 +1226,7 @@ drm_gem_lock_reservations(struct drm_gem_object **objs, int count,
>>>>> ret = dma_resv_lock_slow_interruptible(obj->resv,
>>>>> acquire_ctx);
>>>>> if (ret) {
>>>>> - ww_acquire_done(acquire_ctx);
>>>>> + ww_acquire_fini(acquire_ctx);
>>>>> return ret;
>>>>> }
>>>>> }
>>>>> @@ -1251,7 +1251,7 @@ drm_gem_lock_reservations(struct drm_gem_object **objs, int count,
>>>>> goto retry;
>>>>> }
>>>>> - ww_acquire_done(acquire_ctx);
>>>>> + ww_acquire_fini(acquire_ctx);
>>>>> return ret;
>>>>> }
>>>>> }
>