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>
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index a712fb9..b21b3db 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -105,7 +105,7 @@
*/
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 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) {