>From c1af6a76f8566eeeed049d3cf24635a43b4a83a6 Mon Sep 17 00:00:00 2001
From: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
Date: Sat, 31 May 2014 09:39:22 +0900
Subject: [PATCH 1/5] gpu/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: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
Cc: stable <stable@xxxxxxxxxx> [3.3+]
---
drivers/gpu/drm/ttm/ttm_page_alloc_dma.c | 3 +++
1 files changed, 3 insertions(+), 0 deletions(-)
diff --git a/drivers/gpu/drm/ttm/ttm_page_alloc_dma.c b/drivers/gpu/drm/ttm/ttm_page_alloc_dma.c
index fb8259f..b751fff 100644
--- a/drivers/gpu/drm/ttm/ttm_page_alloc_dma.c
+++ b/drivers/gpu/drm/ttm/ttm_page_alloc_dma.c
@@ -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;
}
--
1.7.1
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