Messages in this thread Patch in this message | | | From | Wen Yang <> | Subject | [PATCH] mm/vmstat: fix divide error at __fragmentation_index | Date | Thu, 3 Aug 2017 15:59:41 +0800 |
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From: Jiang Biao <jiang.biao2@zte.com.cn>
When order is -1 or too big, *1UL << order* will be 0, which will cause divide error like this,
divide error: 0000 [#1] SMP Call Trace: [<ffffffff81168423>] compaction_suitable+0x63/0xc0 [<ffffffff81168a75>] compact_zone+0x35/0x950 [<ffffffff811745b5>] ? free_percpu+0xb5/0x140 [<ffffffff81092b23>] ? schedule_on_each_cpu+0x133/0x160 [<ffffffff8116949c>] compact_node+0x10c/0x120 [<ffffffff8116953c>] sysctl_compaction_handler+0x5c/0x90 [<ffffffff811fa517>] proc_sys_call_handler+0x97/0xd0 [<ffffffff811fa564>] proc_sys_write+0x14/0x20 [<ffffffff81187368>] vfs_write+0xb8/0x1a0 [<ffffffff81187c61>] sys_write+0x51/0x90 [<ffffffff8100b052>] system_call_fastpath+0x16/0x1b
Signed-off-by: Wen Yang <wen.yang99@zte.com.cn> Reviewed-by: Jiang Biao <jiang.biao2@zte.com.cn> --- mm/vmstat.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/mm/vmstat.c b/mm/vmstat.c index 76f7367..2f9d012 100644 --- a/mm/vmstat.c +++ b/mm/vmstat.c @@ -870,6 +870,9 @@ static int __fragmentation_index(unsigned int order, struct contig_page_info *in { unsigned long requested = 1UL << order; + if (!requested) + return 0; + if (!info->free_blocks_total) return 0; -- 2.7.4
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