The patch titled
Subject: mm/memcg: warn on missing memcg on mem_cgroup_page_lruvec()
has been added to the -mm tree. Its filename is
mm-memcontrol-rewrite-mem_cgroup_page_lruvec-fix-fix.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/mm-memcontrol-rewrite-mem_cgroup_page_lruvec-fix-fix.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/mm-memcontrol-rewrite-mem_cgroup_page_lruvec-fix-fix.patch
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------------------------------------------------------
From: Lorenzo Stoakes <lstoakes@xxxxxxxxx>
Subject: mm/memcg: warn on missing memcg on mem_cgroup_page_lruvec()
Move memcg check to mem_cgroup_page_lruvec() as there are callers which
may invoke this with !memcg in mem_cgroup_lruvec(), whereas they should
not in mem_cgroup_page_lruvec().
We expect that we have always charged a page to the memcg before
mem_cgroup_page_lruvec() is invoked, so add a warning to assert that this
is the case.
Link: https://lkml.kernel.org/r/20201125112202.387009-1-lstoakes@xxxxxxxxx
Signed-off-by: Lorenzo Stoakes <lstoakes@xxxxxxxxx>
Reported-by: syzbot+ce635500093181f39c1c@xxxxxxxxxxxxxxxxxxxxxxxxx
Acked-by: Alex Shi <alex.shi@xxxxxxxxxxxxxxxxx>
Cc: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Shakeel Butt <shakeelb@xxxxxxxxxx>
Cc: Roman Gushchin <guro@xxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: Yafang Shao <laoar.shao@xxxxxxxxx>
Cc: Alexander Duyck <alexander.h.duyck@xxxxxxxxxxxxxxx>
Cc: Hui Su <sh_def@xxxxxxx>
Cc: Wei Yang <richard.weiyang@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/memcontrol.h | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
--- a/include/linux/memcontrol.h~mm-memcontrol-rewrite-mem_cgroup_page_lruvec-fix-fix
+++ a/include/linux/memcontrol.h
@@ -618,7 +618,6 @@ static inline struct lruvec *mem_cgroup_
goto out;
}
- VM_WARN_ON_ONCE(!memcg);
if (!memcg)
memcg = root_mem_cgroup;
@@ -645,7 +644,10 @@ out:
static inline struct lruvec *mem_cgroup_page_lruvec(struct page *page,
struct pglist_data *pgdat)
{
- return mem_cgroup_lruvec(page_memcg(page), pgdat);
+ struct mem_cgroup *memcg = page_memcg(page);
+
+ VM_WARN_ON_ONCE_PAGE(!memcg, page);
+ return mem_cgroup_lruvec(memcg, pgdat);
}
static inline bool lruvec_holds_page_lru_lock(struct page *page,
_
Patches currently in -mm which might be from lstoakes@xxxxxxxxx are
mm-memcontrol-rewrite-mem_cgroup_page_lruvec-fix-fix.patch
