Re: [PATCH v2] drm/ttm: Always and only destroy bo->ttm_resv in ttm_bo_release_list

Am 02.11.2017 um 18:22 schrieb Michel Dänzer:

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.

v2:

• Always initialize bo->ttm_resv in ttm_bo_init_reserved (Christian König)

Fixes: 0d2bd2ae045d "drm/ttm: fix memory leak while individualizing BOs" Reviewed-by: Chunming Zhou david1.zhou@amd.com # v1 Signed-off-by: Michel Dänzer michel.daenzer@amd.com

Reviewed-by: Christian König christian.koenig@amd.com

---

drivers/gpu/drm/ttm/ttm_bo.c | 16 ++++------------ 1 file changed, 4 insertions(+), 12 deletions(-)

diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c index 379ec41d2c69..c088703777e2 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);

@@ -402,14 +401,11 @@ static int ttm_bo_individualize_resv(struct ttm_buffer_object *bo) if (bo->resv == &bo->ttm_resv) return 0;

• reservation_object_init(&bo->ttm_resv); 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 +453,8 @@ 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 +554,6 @@ 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);

@@ -1210,8 +1202,8 @@ int ttm_bo_init_reserved(struct ttm_bo_device *bdev, lockdep_assert_held(&bo->resv->lock.base); } else { bo->resv = &bo->ttm_resv;

• reservation_object_init(&bo->ttm_resv);
  

  }

• reservation_object_init(&bo->ttm_resv); atomic_inc(&bo->glob->bo_count); drm_vma_node_reset(&bo->vma_node); bo->priority = 0;