From: Michel Dänzer michel.daenzer@amd.com
Fixes a use-after-free due to a race condition in ttm_bo_cleanup_refs_and_unlock, which allows one task to reserve a BO and destroy its ttm_resv while another task is waiting for it to signal in reservation_object_wait_timeout_rcu.
Fixes: 0d2bd2ae045d "drm/ttm: fix memory leak while individualizing BOs" Signed-off-by: Michel Dänzer michel.daenzer@amd.com --- drivers/gpu/drm/ttm/ttm_bo.c | 13 +++---------- 1 file changed, 3 insertions(+), 10 deletions(-)
diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c index 379ec41d2c69..a19a0ebf32ac 100644 --- a/drivers/gpu/drm/ttm/ttm_bo.c +++ b/drivers/gpu/drm/ttm/ttm_bo.c @@ -150,8 +150,7 @@ static void ttm_bo_release_list(struct kref *list_kref) ttm_tt_destroy(bo->ttm); atomic_dec(&bo->glob->bo_count); dma_fence_put(bo->moving); - if (bo->resv == &bo->ttm_resv) - reservation_object_fini(&bo->ttm_resv); + reservation_object_fini(&bo->ttm_resv); mutex_destroy(&bo->wu_mutex); if (bo->destroy) bo->destroy(bo); @@ -406,10 +405,8 @@ static int ttm_bo_individualize_resv(struct ttm_buffer_object *bo) BUG_ON(!reservation_object_trylock(&bo->ttm_resv));
r = reservation_object_copy_fences(&bo->ttm_resv, bo->resv); - if (r) { + if (r) reservation_object_unlock(&bo->ttm_resv); - reservation_object_fini(&bo->ttm_resv); - }
return r; } @@ -457,10 +454,8 @@ static void ttm_bo_cleanup_refs_or_queue(struct ttm_buffer_object *bo) if (reservation_object_test_signaled_rcu(&bo->ttm_resv, true)) { ttm_bo_del_from_lru(bo); spin_unlock(&glob->lru_lock); - if (bo->resv != &bo->ttm_resv) { + if (bo->resv != &bo->ttm_resv) reservation_object_unlock(&bo->ttm_resv); - reservation_object_fini(&bo->ttm_resv); - }
ttm_bo_cleanup_memtype_use(bo); return; @@ -560,8 +555,6 @@ static int ttm_bo_cleanup_refs_and_unlock(struct ttm_buffer_object *bo, }
ttm_bo_del_from_lru(bo); - if (!list_empty(&bo->ddestroy) && (bo->resv != &bo->ttm_resv)) - reservation_object_fini(&bo->ttm_resv); list_del_init(&bo->ddestroy); kref_put(&bo->list_kref, ttm_bo_ref_bug);