From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tetsuo Handa Subject: [PATCH 1/5] gpu/drm/ttm: Fix possible division by 0 in ttm_dma_pool_shrink_scan(). Date: Sat, 31 May 2014 11:58:35 +0900 Message-ID: <201405311158.DGE64002.QLOOHJSFFMVFOt@I-love.SAKURA.ne.jp> References: <201405242322.AID86423.HOMLQJOtFFVOSF@I-love.SAKURA.ne.jp> <20140528185445.GA23122@phenom.dumpdata.com> <201405290647.DHI69200.HSFVFMFOJOLOQt@I-love.SAKURA.ne.jp> <201405292334.EAG00503.FLOOJFStHVQMFO@I-love.SAKURA.ne.jp> <20140530160824.GD3621@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: In-Reply-To: <20140530160824.GD3621@localhost.localdomain> Sender: linux-kernel-owner@vger.kernel.org To: konrad.wilk@oracle.com Cc: dchinner@redhat.com, airlied@linux.ie, glommer@openvz.org, mgorman@suse.de, linux-mm@kvack.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org List-Id: linux-mm.kvack.org >>From c1af6a76f8566eeeed049d3cf24635a43b4a83a6 Mon Sep 17 00:00:00 2001 From: Tetsuo Handa 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 Cc: stable [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