On Thu, Jun 9, 2016 at 3:29 PM, Rob Clark <robdclark@xxxxxxxxx> wrote: > There were a couple messed up things about this fail path. > (1) it would drop object_name_lock twice > (2) drm_gem_handle_delete() (in drm_gem_remove_prime_handles()) > needs to grab prime_lock > > Reported-by: Alex Deucher <alexdeucher@xxxxxxxxx> > Signed-off-by: Rob Clark <robdclark@xxxxxxxxx> fyi, Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=117861 > --- > Untested, but I think this should fix the potential deadlock that Alex > reported. Would be nice if someone with setup to reproduce could test > this. > > drivers/gpu/drm/drm_prime.c | 10 ++++++---- > 1 file changed, 6 insertions(+), 4 deletions(-) > > diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c > index aab0f3f..780589b 100644 > --- a/drivers/gpu/drm/drm_prime.c > +++ b/drivers/gpu/drm/drm_prime.c > @@ -593,7 +593,7 @@ int drm_gem_prime_fd_to_handle(struct drm_device *dev, > get_dma_buf(dma_buf); > } > > - /* drm_gem_handle_create_tail unlocks dev->object_name_lock. */ > + /* _handle_create_tail unconditionally unlocks dev->object_name_lock. */ > ret = drm_gem_handle_create_tail(file_priv, obj, handle); > drm_gem_object_unreference_unlocked(obj); > if (ret) > @@ -601,11 +601,10 @@ int drm_gem_prime_fd_to_handle(struct drm_device *dev, > > ret = drm_prime_add_buf_handle(&file_priv->prime, > dma_buf, *handle); > + mutex_unlock(&file_priv->prime.lock); > if (ret) > goto fail; > > - mutex_unlock(&file_priv->prime.lock); > - > dma_buf_put(dma_buf); > > return 0; > @@ -615,11 +614,14 @@ fail: > * to detach.. which seems ok.. > */ > drm_gem_handle_delete(file_priv, *handle); > + dma_buf_put(dma_buf); > + return ret; > + > out_unlock: > mutex_unlock(&dev->object_name_lock); > out_put: > - dma_buf_put(dma_buf); > mutex_unlock(&file_priv->prime.lock); > + dma_buf_put(dma_buf); > return ret; > } > EXPORT_SYMBOL(drm_gem_prime_fd_to_handle); > -- > 2.5.5 > _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
