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List:       linux-mm-commits
Subject:    + mm-fix-division-by-0-in-percpu_pagelist_fraction.patch added to -mm tree
From:       akpm () linux-foundation ! org
Date:       2012-04-30 22:42:32
Message-ID: 20120430224232.B64DDA00AA () akpm ! mtv ! corp ! google ! com
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The patch titled
     Subject: mm: fix division by 0 in percpu_pagelist_fraction()
has been added to the -mm tree.  Its filename is
     mm-fix-division-by-0-in-percpu_pagelist_fraction.patch

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------------------------------------------------------
From: Sasha Levin <levinsasha928@gmail.com>
Subject: mm: fix division by 0 in percpu_pagelist_fraction()

percpu_pagelist_fraction_sysctl_handler() has only considered -EINVAL as a
possible error from proc_dointvec_minmax().  If any other error is
returned, it would proceed to divide by zero since
percpu_pagelist_fraction wasn't getting initialized at any point.  For
example, writing 0 bytes into the proc file would trigger the issue.

Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
Reviewed-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/page_alloc.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff -puN mm/page_alloc.c~mm-fix-division-by-0-in-percpu_pagelist_fraction mm/page_alloc.c
--- a/mm/page_alloc.c~mm-fix-division-by-0-in-percpu_pagelist_fraction
+++ a/mm/page_alloc.c
@@ -106,7 +106,7 @@ unsigned long totalreserve_pages __read_
  */
 unsigned long dirty_balance_reserve __read_mostly;
 
-int percpu_pagelist_fraction;
+int percpu_pagelist_fraction = 8;
 gfp_t gfp_allowed_mask __read_mostly = GFP_BOOT_MASK;
 
 #ifdef CONFIG_PM_SLEEP
@@ -5271,7 +5271,7 @@ int percpu_pagelist_fraction_sysctl_hand
 	int ret;
 
 	ret = proc_dointvec_minmax(table, write, buffer, length, ppos);
-	if (!write || (ret == -EINVAL))
+	if (!write || (ret < 0))
 		return ret;
 	for_each_populated_zone(zone) {
 		for_each_possible_cpu(cpu) {
_
Subject: Subject: mm: fix division by 0 in percpu_pagelist_fraction()

Patches currently in -mm which might be from levinsasha928@gmail.com are

linux-next.patch
mm-fix-division-by-0-in-percpu_pagelist_fraction.patch
brlocks-lglocks-cleanups.patch

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