From: Alex Shi <alex.shi@linux.alibaba.com>
To: Lorenzo Stoakes <lstoakes@gmail.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>
Subject: Re: [PATCH] mm/memcg: warn on missing memcg on mem_cgroup_page_lruvec()
Date: Wed, 25 Nov 2020 20:15:11 +0800 [thread overview]
Message-ID: <0918d6f5-8459-7b5e-82a3-6c9792d17433@linux.alibaba.com> (raw)
In-Reply-To: <20201125112202.387009-1-lstoakes@gmail.com>
Acked-by: Alex Shi <alex.shi@linux.alibaba.com>
在 2020/11/25 下午7:22, Lorenzo Stoakes 写道:
> 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,
>
next prev parent reply other threads:[~2020-11-25 12:15 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 ` [PATCH] mm/memcg: warn on missing memcg on mem_cgroup_page_lruvec() Lorenzo Stoakes
2020-11-25 12:15 ` Alex Shi [this message]
2020-11-25 22:27 ` Stephen Rothwell
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