Commit 5557e946 authored Jun 30, 2022 by Dmitry Osipenko Committed by Greg Kroah-Hartman Aug 25, 2022

drm/gem: Properly annotate WW context on drm_gem_lock_reservations() error

commit 2939deac1fa220bc82b89235f146df1d9b52e876 upstream.

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: stable@vger.kernel.org
Fixes: 7edc3e3b ("drm: Add helpers for locking an array of BO reservations.")
Reviewed-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20220630200405.1883897-2-dmitry.osipenko@collabora.com

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent b8f3830c

drivers/gpu/drm/drm_gem.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -1292,7 +1292,7 @@ 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;
		}
		}
		@@ -1317,7 +1317,7 @@ 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;
		}
		}