diff options
| author | Wen Yang <wen.yang99@zte.com.cn> | 2017-09-06 16:24:06 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-09-06 17:27:29 -0700 |
| commit | 88d6ac40c1c6b2334046d3f89f1911a3c8febd4c (patch) | |
| tree | 15b853c5e0a033d0b69ccfb28b3fbdb30baad430 /mm/vmstat.c | |
| parent | 79b63f12abcbbd2caf7064b294af648a87de07ff (diff) | |
| download | lwn-88d6ac40c1c6b2334046d3f89f1911a3c8febd4c.tar.gz lwn-88d6ac40c1c6b2334046d3f89f1911a3c8febd4c.zip | |
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>
Diffstat (limited to 'mm/vmstat.c')
| -rw-r--r-- | mm/vmstat.c | 3 |
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; |