| From | Jiri Slaby <> | Subject | [PATCH 3.12 126/142] drm/ttm: Fix possible division by 0 in ttm_dma_pool_shrink_scan(). | Date | Fri, 26 Sep 2014 11:45:37 +0200 |
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From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
3.12-stable review patch. If anyone has any objections, please let me know.
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commit 11e504cc705e8ccb06ac93a276e11b5e8fee4d40 upstream.
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: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Signed-off-by: Dave Airlie <airlied@redhat.com> Signed-off-by: Jiri Slaby <jslaby@suse.cz> --- drivers/gpu/drm/ttm/ttm_page_alloc_dma.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/drivers/gpu/drm/ttm/ttm_page_alloc_dma.c b/drivers/gpu/drm/ttm/ttm_page_alloc_dma.c index 7957beeeaf73..eeb8527aba90 100644 --- a/drivers/gpu/drm/ttm/ttm_page_alloc_dma.c +++ b/drivers/gpu/drm/ttm/ttm_page_alloc_dma.c @@ -1014,6 +1014,8 @@ 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; @@ -1033,6 +1035,7 @@ 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; } -- 2.1.0
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