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From:   Dmitry Osipenko <dmitry.osipenko@collabora.com>
To:     David Airlie <airlied@linux.ie>, Gerd Hoffmann <kraxel@redhat.com>,
        Gurchetan Singh <gurchetansingh@chromium.org>,
        Chia-I Wu <olvaffe@gmail.com>, Daniel Vetter <daniel@ffwll.ch>,
        Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
        Maxime Ripard <mripard@kernel.org>,
        Thomas Zimmermann <tzimmermann@suse.de>,
        Emil Velikov <emil.l.velikov@gmail.com>,
        =?UTF-8?q?Christian=20K=C3=B6nig?= <christian.koenig@amd.com>,
        =?UTF-8?q?Thomas=20Hellstr=C3=B6m?= <thomas_os@shipmail.org>
Cc:     dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org,
        Dmitry Osipenko <digetx@gmail.com>,
        linux-tegra@vger.kernel.org, kernel@collabora.com,
        virtualization@lists.linux-foundation.org
Subject: [PATCH v7 1/2] drm/gem: Properly annotate WW context on drm_gem_lock_reservations() error
Date:   Thu, 30 Jun 2022 23:04:04 +0300
Message-Id: <20220630200405.1883897-2-dmitry.osipenko@collabora.com>
In-Reply-To: <20220630200405.1883897-1-dmitry.osipenko@collabora.com>
References: <20220630200405.1883897-1-dmitry.osipenko@collabora.com>
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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: 7edc3e3b975b5 ("drm: Add helpers for locking an array of BO reservations.")
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;
 		}
 	}
-- 
2.36.1