]> www.infradead.org Git - nvme.git/commit
mm: memcontrol: fix swap counter leak from offline cgroup
authorMuchun Song <songmuchun@bytedance.com>
Thu, 6 Mar 2025 02:31:33 +0000 (10:31 +0800)
committerAndrew Morton <akpm@linux-foundation.org>
Mon, 17 Mar 2025 00:40:24 +0000 (17:40 -0700)
commit73f839b6d2ed75f281bd75aeb68e81bce373bdee
treec16eddc1ff554a9a869796f0b81c86d0ed704703
parent8c6ff7f181786d0b296bb0f1bf269ca8770632c9
mm: memcontrol: fix swap counter leak from offline cgroup

Commit 6769183166b3 removed the parameter of id from swap_cgroup_record()
and get the memcg id from mem_cgroup_id(folio_memcg(folio)).  However, the
caller of it may update a different memcg's counter instead of
folio_memcg(folio).

E.g.  in the caller of mem_cgroup_swapout(), @swap_memcg could be
different with @memcg and update the counter of @swap_memcg, but
swap_cgroup_record() records the wrong memcg's ID.  When it is uncharged
from __mem_cgroup_uncharge_swap(), the swap counter will leak since the
wrong recorded ID.

Fix it by bringing the parameter of id back.

Link: https://lkml.kernel.org/r/20250306023133.44838-1-songmuchun@bytedance.com
Fixes: 6769183166b3 ("mm/swap_cgroup: decouple swap cgroup recording and clearing")
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Kairui Song <kasong@tencent.com>
Cc: Chris Li <chrisl@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
include/linux/swap_cgroup.h
mm/memcontrol.c
mm/swap_cgroup.c