From: Michel Dänzer <michel.daenzer@xxxxxxx>
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@xxxxxxx>
---
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);
--
2.15.0.rc2
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