[Linaro-mm-sig] Re: [PATCH v6 01/22] drm/gem: Properly annotate WW context on drm_gem_lock_reservations() error

Hi,

On 5/27/22 01:50, Dmitry Osipenko wrote:

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 needs to be annotated as "freed"

s /WW/ww_acquire_context/ ? s /"freed"/"released"/ ?

, which fixes the noisy "WARNING: held lock freed!" splat of VirtIO-GPU driver with CONFIG_DEBUG_MUTEXES=y and enabled lockdep.

Cc: stable@vger.kernel.org

Can you dig up the commit in error and add a Fixes: Tag?

Using that and "dim fixes" will also make the Cc: stable tag a bit more verbose.

With that fixed,

Reviewed-by: Thomas Hellström thomas.hellstrom@linux.intel.com

Signed-off-by: Dmitry Osipenko dmitry.osipenko@collabora.com

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;
  

  } }