Commit 0c0816d6 authored by Danilo Krummrich's avatar Danilo Krummrich
Browse files

drm/gem: fix lockdep check for dma-resv lock 



When no custom lock is set to protect a GEMs GPUVA list, lockdep checks
should fall back to the GEM objects dma-resv lock. With the current
implementation we're setting the lock_dep_map of the GEM objects 'resv'
pointer (in case no custom lock_dep_map is set yet) on
drm_gem_private_object_init().

However, the GEM objects 'resv' pointer might still change after
drm_gem_private_object_init() is called, e.g. through
ttm_bo_init_reserved(). This can result in the wrong lock being tracked.

To fix this, call dma_resv_held() directly from
drm_gem_gpuva_assert_lock_held() and fall back to the GEMs lock_dep_map
pointer only if an actual custom lock is set.

Fixes: e6303f32 ("drm: manager to keep track of GPUs VA mappings")
Reviewed-by: default avatarDave Airlie <airlied@redhat.com>
Signed-off-by: default avatarDanilo Krummrich <dakr@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230804182406.5222-2-dakr@redhat.com
parent a5ae331e

include/drm/drm_gem.h

+9 −6
Original line number Diff line number Diff line
@@ -551,15 +551,17 @@ int drm_gem_evict(struct drm_gem_object *obj); 
 * @lock: the lock used to protect the gpuva list. The locking primitive

 * must contain a dep_map field.

 *

 * Call this if you're not proctecting access to the gpuva list

 * with the dma-resv lock, otherwise, drm_gem_gpuva_init() takes care

 * of initializing lock_dep_map for you.

 * Call this if you're not proctecting access to the gpuva list with the

 * dma-resv lock, but with a custom lock.

 */

#define drm_gem_gpuva_set_lock(obj, lock) \

	if (!(obj)->gpuva.lock_dep_map) \

	if (!WARN((obj)->gpuva.lock_dep_map, \

		  "GEM GPUVA lock should be set only once.")) \

		(obj)->gpuva.lock_dep_map = &(lock)->dep_map

#define drm_gem_gpuva_assert_lock_held(obj) \

	lockdep_assert(lock_is_held((obj)->gpuva.lock_dep_map))

	lockdep_assert((obj)->gpuva.lock_dep_map ? \

		       lock_is_held((obj)->gpuva.lock_dep_map) : \

		       dma_resv_held((obj)->resv))

#else

#define drm_gem_gpuva_set_lock(obj, lock) do {} while (0)

#define drm_gem_gpuva_assert_lock_held(obj) do {} while (0)
@@ -573,11 +575,12 @@ int drm_gem_evict(struct drm_gem_object *obj); 
 *

 * Calling this function is only necessary for drivers intending to support the

 * &drm_driver_feature DRIVER_GEM_GPUVA.

 *

 * See also drm_gem_gpuva_set_lock().

 */

static inline void drm_gem_gpuva_init(struct drm_gem_object *obj)

{

	INIT_LIST_HEAD(&obj->gpuva.list);

	drm_gem_gpuva_set_lock(obj, &obj->resv->lock.base);

}



/**