When order is -1 or too big, *1UL << order* will be 0, which will
cause 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.
Sugguested-by: VlastimilBabka <vbabka@xxxxxxx>
Signed-off-by: Wen Yang <wen.yang99@xxxxxxxxxx>
Reviewed-by: Jiang Biao <jiang.biao2@xxxxxxxxxx>
---
mm/vmstat.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/mm/vmstat.c b/mm/vmstat.c
index 76f7367..6f0f1ae 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;
--
2.7.4
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@xxxxxxxxx. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>
