When list_for_each_entry() completes the iteration over the whole list without breaking the loop, the iterator value will be a bogus pointer computed based on the head element.
While it is safe to use the pointer to determine if it was computed based on the head element with &pos->member == head, using the iterator variable after the loop should be avoided. In preparation to limiting the scope of a list iterator to the list traversal loop, use a dedicated pointer to point to the found element [1]. Link: https://lore.kernel.org/all/yhdfeiwi4edth...@kroah.com/ Signed-off-by: Xiaomeng Tong <xiam0nd.t...@gmail.com> --- drivers/gpu/drm/ttm/ttm_bo.c | 20 ++++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-) diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c index db3dc7ef5382..413b5bbf2414 100644 --- a/drivers/gpu/drm/ttm/ttm_bo.c +++ b/drivers/gpu/drm/ttm/ttm_bo.c @@ -673,36 +673,36 @@ int ttm_mem_evict_first(struct ttm_device *bdev, struct ww_acquire_ctx *ticket) { struct ttm_buffer_object *bo = NULL, *busy_bo = NULL; + struct ttm_buffer_object *iter; bool locked = false; unsigned i; int ret; spin_lock(&bdev->lru_lock); for (i = 0; i < TTM_MAX_BO_PRIORITY; ++i) { - list_for_each_entry(bo, &man->lru[i], lru) { + list_for_each_entry(iter, &man->lru[i], lru) { bool busy; - if (!ttm_bo_evict_swapout_allowable(bo, ctx, place, + if (!ttm_bo_evict_swapout_allowable(iter, ctx, place, &locked, &busy)) { if (busy && !busy_bo && ticket != - dma_resv_locking_ctx(bo->base.resv)) - busy_bo = bo; + dma_resv_locking_ctx(iter->base.resv)) + busy_bo = iter; continue; } - if (!ttm_bo_get_unless_zero(bo)) { + if (!ttm_bo_get_unless_zero(iter)) { if (locked) - dma_resv_unlock(bo->base.resv); + dma_resv_unlock(iter->base.resv); continue; } + + bo = iter; break; } - /* If the inner loop terminated early, we have our candidate */ - if (&bo->lru != &man->lru[i]) + if (bo) break; - - bo = NULL; } if (!bo) { -- 2.17.1
