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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>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Sasha Levin 2012-05-10 13:01:44 -07:00 committed by Linus Torvalds
parent 16fbdce62d
commit 93278814d3
1 changed files with 2 additions and 2 deletions
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4
mm/page_alloc.c
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@ -105,7 +105,7 @@ unsigned long totalreserve_pages __read_mostly;
*/
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
@ -5203,7 +5203,7 @@ int percpu_pagelist_fraction_sysctl_handler(ctl_table *table, int write,
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) {