lkml.org 
[lkml]   [2014]   [Sep]   [26]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 3.12 126/142] drm/ttm: Fix possible division by 0 in ttm_dma_pool_shrink_scan().
Date
From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>

3.12-stable review patch. If anyone has any objections, please let me know.

===============

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


\
 
 \ /
  Last update: 2014-09-26 12:21    [W:0.355 / U:0.856 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site