This is a note to let you know that I've just added the patch titled

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

to the 3.16-stable tree which can be found at:
    
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     drm-ttm-fix-possible-division-by-0-in-ttm_dma_pool_shrink_scan.patch
and it can be found in the queue-3.16 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.


>From 11e504cc705e8ccb06ac93a276e11b5e8fee4d40 Mon Sep 17 00:00:00 2001
From: Tetsuo Handa <[email protected]>
Date: Sun, 3 Aug 2014 19:59:35 +0900
Subject: drm/ttm: Fix possible division by 0 in ttm_dma_pool_shrink_scan().

From: Tetsuo Handa <[email protected]>

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 <[email protected]>
Signed-off-by: Dave Airlie <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

---
 drivers/gpu/drm/ttm/ttm_page_alloc_dma.c |    3 +++
 1 file changed, 3 insertions(+)

--- 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
                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
                         p->pool->dev_name, p->pool->name, current->pid,
                         nr_free, shrink_pages);
        }
+out:
        mutex_unlock(&_manager->lock);
        return freed;
 }


Patches currently in stable-queue which might be from 
[email protected] are

queue-3.16/drm-ttm-fix-possible-stack-overflow-by-recursive-shrinker-calls.patch
queue-3.16/drm-ttm-fix-possible-division-by-0-in-ttm_dma_pool_shrink_scan.patch
queue-3.16/drm-ttm-choose-a-pool-to-shrink-correctly-in-ttm_dma_pool_shrink_scan.patch
queue-3.16/drm-ttm-use-mutex_trylock-to-avoid-deadlock-inside-shrinker-functions.patch
queue-3.16/drm-ttm-pass-gfp-flags-in-order-to-avoid-deadlock.patch
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