diff options
| author | Boris Brezillon <boris.brezillon@collabora.com> | 2020-11-01 18:40:16 +0100 |
|---|---|---|
| committer | Boris Brezillon <boris.brezillon@collabora.com> | 2020-11-03 09:21:52 +0100 |
| commit | 7d2d6d01293e6d9b42a6cb410be4158571f7fe9d (patch) | |
| tree | 6e84f668bfa351c9d31383e327e14202d8efaf03 /drivers/gpu | |
| parent | dcda7c28bff2662a44c0adaf87c08031bebeb7d8 (diff) | |
drm/panfrost: Fix a deadlock between the shrinker and madvise path
panfrost_ioctl_madvise() and panfrost_gem_purge() acquire the mappings
and shmem locks in different orders, thus leading to a potential
the mappings lock first.
Fixes: bdefca2d8dc0 ("drm/panfrost: Add the panfrost_gem_mapping concept")
Cc: <stable@vger.kernel.org>
Cc: Christian Hewitt <christianshewitt@gmail.com>
Reported-by: Christian Hewitt <christianshewitt@gmail.com>
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Reviewed-by: Steven Price <steven.price@arm.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201101174016.839110-1-boris.brezillon@collabora.com
Diffstat (limited to 'drivers/gpu')
| -rw-r--r-- | drivers/gpu/drm/panfrost/panfrost_gem.c | 4 | ||||
| -rw-r--r-- | drivers/gpu/drm/panfrost/panfrost_gem.h | 2 | ||||
| -rw-r--r-- | drivers/gpu/drm/panfrost/panfrost_gem_shrinker.c | 14 |
3 files changed, 13 insertions, 7 deletions
diff --git a/drivers/gpu/drm/panfrost/panfrost_gem.c b/drivers/gpu/drm/panfrost/panfrost_gem.c index 1a6cea0e0bd7..62d4d710a571 100644 --- a/drivers/gpu/drm/panfrost/panfrost_gem.c +++ b/drivers/gpu/drm/panfrost/panfrost_gem.c @@ -105,14 +105,12 @@ void panfrost_gem_mapping_put(struct panfrost_gem_mapping *mapping) kref_put(&mapping->refcount, panfrost_gem_mapping_release); } -void panfrost_gem_teardown_mappings(struct panfrost_gem_object *bo) +void panfrost_gem_teardown_mappings_locked(struct panfrost_gem_object *bo) { struct panfrost_gem_mapping *mapping; - mutex_lock(&bo->mappings.lock); list_for_each_entry(mapping, &bo->mappings.list, node) panfrost_gem_teardown_mapping(mapping); - mutex_unlock(&bo->mappings.lock); } int panfrost_gem_open(struct drm_gem_object *obj, struct drm_file *file_priv) diff --git a/drivers/gpu/drm/panfrost/panfrost_gem.h b/drivers/gpu/drm/panfrost/panfrost_gem.h index b3517ff9630c..8088d5fd8480 100644 --- a/drivers/gpu/drm/panfrost/panfrost_gem.h +++ b/drivers/gpu/drm/panfrost/panfrost_gem.h @@ -82,7 +82,7 @@ struct panfrost_gem_mapping * panfrost_gem_mapping_get(struct panfrost_gem_object *bo, struct panfrost_file_priv *priv); void panfrost_gem_mapping_put(struct panfrost_gem_mapping *mapping); -void panfrost_gem_teardown_mappings(struct panfrost_gem_object *bo); +void panfrost_gem_teardown_mappings_locked(struct panfrost_gem_object *bo); void panfrost_gem_shrinker_init(struct drm_device *dev); void panfrost_gem_shrinker_cleanup(struct drm_device *dev); diff --git a/drivers/gpu/drm/panfrost/panfrost_gem_shrinker.c b/drivers/gpu/drm/panfrost/panfrost_gem_shrinker.c index 288e46c40673..1b9f68d8e9aa 100644 --- a/drivers/gpu/drm/panfrost/panfrost_gem_shrinker.c +++ b/drivers/gpu/drm/panfrost/panfrost_gem_shrinker.c @@ -40,18 +40,26 @@ static bool panfrost_gem_purge(struct drm_gem_object *obj) { struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj); struct panfrost_gem_object *bo = to_panfrost_bo(obj); + bool ret = false; if (atomic_read(&bo->gpu_usecount)) return false; - if (!mutex_trylock(&shmem->pages_lock)) + if (!mutex_trylock(&bo->mappings.lock)) return false; - panfrost_gem_teardown_mappings(bo); + if (!mutex_trylock(&shmem->pages_lock)) + goto unlock_mappings; + + panfrost_gem_teardown_mappings_locked(bo); drm_gem_shmem_purge_locked(obj); + ret = true; mutex_unlock(&shmem->pages_lock); - return true; + +unlock_mappings: + mutex_unlock(&bo->mappings.lock); + return ret; } static unsigned long |