From 078c6c3a5e7dc53a9a23408cc32c83954abb5d0d Mon Sep 17 00:00:00 2001
From: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Date: Thu, 11 Feb 2016 16:13:06 -0800
Subject: mm/backing-dev.c: fix error path in wb_init()

We need to use post-decrement to get percpu_counter_destroy() called on
&wb->stat[0].  Moreover, the pre-decremebt would cause infinite
out-of-bounds accesses if the setup code failed at i==0.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Vladimir Davydov <vdavydov@virtuozzo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 mm/backing-dev.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

(limited to 'mm/backing-dev.c')

diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index 926c76d56388..c554d173a65f 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -328,7 +328,7 @@ static int wb_init(struct bdi_writeback *wb, struct backing_dev_info *bdi,
 	return 0;
 
 out_destroy_stat:
-	while (--i)
+	while (i--)
 		percpu_counter_destroy(&wb->stat[i]);
 	fprop_local_destroy_percpu(&wb->completions);
 out_put_cong:
-- 
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