The kernel currently allows dying tasks to exceed the memcg limits.
The allocation is expected to be the last one and the occupied memory
will be freed soon.
This is not always true because it can be part of the huge vmalloc
allocation. Allowed once, they will repeat over and over again.
Moreover lifetime of the allocated object can differ from
In addition the lifetime of the dying task.
Multiple such allocations running concurrently can not only overuse
the memcg limit, but can lead to a global out of memory and,
in the worst case, cause the host to panic.

Signed-off-by: Vasily Averin <redacted>
---
 mm/memcontrol.c | 23 +++++------------------
 1 file changed, 5 insertions(+), 18 deletions(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 389b5766e74f..67195fcfbddf 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c

@@ -1834,6 +1834,9 @@ static enum oom_status mem_cgroup_oom(struct mem_cgroup *memcg, gfp_t mask, int
 		return OOM_ASYNC;
 	}
 
+	if (should_force_charge())
+		return OOM_SKIPPED;