From: Muchun Song <muchun.song@linux.dev>
To: Jiayuan Chen <jiayuan.chen@linux.dev>
Cc: linux-mm@kvack.org, stable@vger.kernel.org,
syzbot+ced4d9a8cadb5ef3adae@syzkaller.appspotmail.com,
Johannes Weiner <hannes@cmpxchg.org>,
Michal Hocko <mhocko@kernel.org>,
Roman Gushchin <roman.gushchin@linux.dev>,
Shakeel Butt <shakeel.butt@linux.dev>,
Andrew Morton <akpm@linux-foundation.org>,
Yosry Ahmed <yosry@kernel.org>, Chris Li <chrisl@kernel.org>,
Jens Axboe <axboe@kernel.dk>, Jan Kara <jack@suse.cz>,
Tejun Heo <tj@kernel.org>,
cgroups@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mm/memcontrol: fix data-race on reading jiffies_64
Date: Thu, 27 Aug 2026 11:08:20 +0800 [thread overview]
Message-ID: <73260DE5-E87A-41BD-BF5F-37163DDD25B4@linux.dev> (raw)
In-Reply-To: <20260827025457.116191-1-jiayuan.chen@linux.dev>
> On Aug 27, 2026, at 10:54, Jiayuan Chen <jiayuan.chen@linux.dev> wrote:
>
> KCSAN reported a data-race between tick_do_update_jiffies64() updating
> jiffies_64 and mem_cgroup_flush_stats_ratelimited() reading it directly.
>
> Unlike jiffies, jiffies_64 is not volatile, so raw reads are plain
> accesses and can even be torn on 32-bit. Use get_jiffies_64() instead,
> and fix the same pattern in mem_cgroup_flush_foreign().
>
> Cc: <stable@vger.kernel.org>
> Fixes: 508bed884767 ("mm: memcg: change flush_next_time to flush_last_time")
> Fixes: 97b27821b485 ("writeback, memcg: Implement foreign dirty flushing")
> Reported-by: syzbot+ced4d9a8cadb5ef3adae@syzkaller.appspotmail.com
> Signed-off-by: Jiayuan Chen <jiayuan.chen@linux.dev>
Acked-by: Muchun Song <muchun.song@linux.dev>
Thanks.
next prev parent reply other threads:[~2026-08-27 3:08 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-27 2:54 [PATCH] mm/memcontrol: fix data-race on reading jiffies_64 Jiayuan Chen
2026-08-27 3:08 ` Muchun Song [this message]
2026-08-27 14:16 ` Michal Hocko
2026-08-27 14:59 ` Johannes Weiner
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=73260DE5-E87A-41BD-BF5F-37163DDD25B4@linux.dev \
--to=muchun.song@linux.dev \
--cc=akpm@linux-foundation.org \
--cc=axboe@kernel.dk \
--cc=cgroups@vger.kernel.org \
--cc=chrisl@kernel.org \
--cc=hannes@cmpxchg.org \
--cc=jack@suse.cz \
--cc=jiayuan.chen@linux.dev \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mhocko@kernel.org \
--cc=roman.gushchin@linux.dev \
--cc=shakeel.butt@linux.dev \
--cc=stable@vger.kernel.org \
--cc=syzbot+ced4d9a8cadb5ef3adae@syzkaller.appspotmail.com \
--cc=tj@kernel.org \
--cc=yosry@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox