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authorWen Yang <wen.yang99@zte.com.cn>2017-09-06 16:24:06 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2017-09-06 17:27:29 -0700
commit88d6ac40c1c6b2334046d3f89f1911a3c8febd4c (patch)
tree15b853c5e0a033d0b69ccfb28b3fbdb30baad430
parent79b63f12abcbbd2caf7064b294af648a87de07ff (diff)
downloadlinux-88d6ac40c1c6b2334046d3f89f1911a3c8febd4c.tar.bz2
mm/vmstat: fix divide error at __fragmentation_index
When order is -1 or too big, *1UL << order* will be 0, which will cause a divide error. Although it seems that all callers of __fragmentation_index() will only do so with a valid order, the patch can make it more robust. Should prevent reoccurrences of https://bugzilla.kernel.org/show_bug.cgi?id=196555 Link: http://lkml.kernel.org/r/1501751520-2598-1-git-send-email-wen.yang99@zte.com.cn Signed-off-by: Wen Yang <wen.yang99@zte.com.cn> Reviewed-by: Jiang Biao <jiang.biao2@zte.com.cn> Suggested-by: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/vmstat.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/mm/vmstat.c b/mm/vmstat.c
index ba9b202e8500..05de233a6fca 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 (WARN_ON_ONCE(order >= MAX_ORDER))
+ return 0;
+
if (!info->free_blocks_total)
return 0;