The commit is pushed to "branch-rh7-3.10.0-1127.vz7.150.x-ovz" and will appear
at https://src.openvz.org/scm/ovz/vzkernel.git
after rh7-3.10.0-1127.vz7.150.10
------>
commit fc1363c056f354c9519148234d6aa709a9d3577f
Author: Kirill Tkhai <[email protected]>
Date: Fri May 15 14:36:05 2020 +0300
mm: Warn on zero uncharge in memcg_uncharge_kmem()
page_counter_uncharge() must return 0 only on the final uncharge of kmem,
but memcg_uncharge_kmem(0) may bring to use-after-free after it.
WARN to find callers, who charge for 0.
Signed-off-by: Kirill Tkhai <[email protected]>
---
mm/memcontrol.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index c3586e8e27ca2..010d580f39ccc 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -3508,6 +3508,9 @@ void memcg_uncharge_kmem(struct mem_cgroup *memcg,
{
u64 kmem;
+ if (WARN_ON_ONCE(!nr_pages))
+ return;
+
kmem = page_counter_uncharge(&memcg->kmem, nr_pages);
page_counter_uncharge(&memcg->memory, nr_pages);
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