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Commit 11e504cc authored by Tetsuo Handa's avatar Tetsuo Handa Committed by Dave Airlie
Browse files

drm/ttm: Fix possible division by 0 in ttm_dma_pool_shrink_scan(). 



list_empty(&_manager->pools) being false before taking _manager->lock
does not guarantee that _manager->npools != 0 after taking _manager->lock
because _manager->npools is updated under _manager->lock.

Signed-off-by: default avatarTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: stable <stable@kernel.org> [3.3+]
Signed-off-by: default avatarDave Airlie <airlied@redhat.com>
parent 74cd62ea

drivers/gpu/drm/ttm/ttm_page_alloc_dma.c

+3 −0
Original line number Diff line number Diff line
@@ -1015,6 +1015,8 @@ ttm_dma_pool_shrink_scan(struct shrinker *shrink, struct shrink_control *sc) 
		return SHRINK_STOP;



	mutex_lock(&_manager->lock);

	if (!_manager->npools)

		goto out;

	pool_offset = pool_offset % _manager->npools;

	list_for_each_entry(p, &_manager->pools, pools) {

		unsigned nr_free;
@@ -1034,6 +1036,7 @@ ttm_dma_pool_shrink_scan(struct shrinker *shrink, struct shrink_control *sc) 
			 p->pool->dev_name, p->pool->name, current->pid,

			 nr_free, shrink_pages);

	}

out:

	mutex_unlock(&_manager->lock);

	return freed;

}