From: Lorenzo Stoakes <lstoakes@gmail.com>
To: Alex Shi <alex.shi@linux.alibaba.com>,
Johannes Weiner <hannes@cmpxchg.org>, Hui Su <sh_def@163.com>,
Stephen Rothwell <sfr@canb.auug.org.au>,
Shakeel Butt <shakeelb@google.com>, Roman Gushchin <guro@fb.com>
Cc: syzbot <syzbot+ce635500093181f39c1c@syzkaller.appspotmail.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
linux-mm <linux-mm@kvack.org>,
Linux-Next Mailing List <linux-next@vger.kernel.org>,
syzkaller-bugs <syzkaller-bugs@googlegroups.com>,
Lorenzo Stoakes <lstoakes@gmail.com>
Subject: [PATCH] mm/memcg: warn on missing memcg on mem_cgroup_page_lruvec()
Date: Wed, 25 Nov 2020 11:22:02 +0000 [thread overview]
Message-ID: <20201125112202.387009-1-lstoakes@gmail.com> (raw)
In-Reply-To: <00000000000054aea005b4d59e71@google.com>
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.
Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com>
Reported-by: syzbot+ce635500093181f39c1c@syzkaller.appspotmail.com
---
include/linux/memcontrol.h | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 87ed56dc75f9..3e6a1df3bdb9 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -618,7 +618,6 @@ static inline struct lruvec *mem_cgroup_lruvec(struct mem_cgroup *memcg,
goto out;
}
- VM_WARN_ON_ONCE(!memcg);
if (!memcg)
memcg = root_mem_cgroup;
@@ -645,7 +644,10 @@ static inline struct lruvec *mem_cgroup_lruvec(struct mem_cgroup *memcg,
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,
--
2.29.2
next prev parent reply other threads:[~2020-11-25 11:22 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-24 7:54 linux-next boot error: WARNING in prepare_kswapd_sleep syzbot
2020-11-24 17:59 ` Lorenzo Stoakes
2020-11-25 6:24 ` Alex Shi
2020-11-25 11:25 ` Lorenzo Stoakes
2020-11-25 11:22 ` Lorenzo Stoakes [this message]
2020-11-25 12:15 ` [PATCH] mm/memcg: warn on missing memcg on mem_cgroup_page_lruvec() Alex Shi
2020-11-25 22:27 ` Stephen Rothwell
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