Naoya-san reports that page->lru of hugetlb pages gets corrupted when
they hit the uncharge path from put_page().
Add a preliminary check for whether the page is even a valid memcg
page before messing with it's ->lru list.
Reported-by: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx>
---
mm/memcontrol.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index b2f924359e79..0eb1eaa2f1ff 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -6606,9 +6606,16 @@ static void uncharge_list(struct list_head *page_list)
*/
void mem_cgroup_uncharge(struct page *page)
{
+ struct page_cgroup *pc;
+
if (mem_cgroup_disabled())
return;
+ /* Don't touch page->lru of any random page, pre-check: */
+ pc = lookup_page_cgroup(page);
+ if (!PageCgroupUsed(pc))
+ return;
+
INIT_LIST_HEAD(&page->lru);
uncharge_list(&page->lru);
}
--
2.0.0
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