+ mm-memcontrol-rewrite-mem_cgroup_page_lruvec-fix-fix.patch added to -mm tree

+ mm-memcontrol-rewrite-mem_cgroup_page_lruvec-fix-fix.patch added to -mm tree

[akpm]

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@gmail.com>
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@gmail.com
Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com>
Reported-by: syzbot+ce635500093181f39c1c@syzkaller.appspotmail.com
Acked-by: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Yafang Shao <laoar.shao@gmail.com>
Cc: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Cc: Hui Su <sh_def@163.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 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@gmail.com are

mm-memcontrol-rewrite-mem_cgroup_page_lruvec-fix-fix.patch