From: "Yu Kuai" <yukuai@fnnas.com>
To: "Tao Cui" <cui.tao@linux.dev>, <axboe@kernel.dk>,
"yu kuai" <yukuai@fygo.io>
Cc: <tj@kernel.org>, <josef@toxicpanda.com>, <yukuai@fygo.io>,
<cgroups@vger.kernel.org>, <linux-block@vger.kernel.org>,
<linux-kernel@vger.kernel.org>, "Tao Cui" <cuitao@kylinos.cn>
Subject: Re: [PATCH] block/blk-cgroup-rwstat: use data_race() for online test
Date: Mon, 3 Aug 2026 13:29:35 +0800 [thread overview]
Message-ID: <95905ed3-dc3f-410d-a530-e26724839d79@fnnas.com> (raw)
In-Reply-To: <20260802150413.29789-1-cui.tao@linux.dev>
在 2026/8/2 23:04, Tao Cui 写道:
> From: Tao Cui<cuitao@kylinos.cn>
>
> blkg_rwstat_recursive_sum() reads pos_blkg->online without the queue
> lock that its doc comment requires, since blkcg_print_blkgs() stopped
> holding it in 56cc24f59c14. Concurrent blkg_create/destroy flips
> ->online, tripping KCSAN. The race is harmless (RCU-protected, stale
> online only causes minor stat noise). Use data_race() to annotate
> the intentional lockless read.
>
> Signed-off-by: Tao Cui<cuitao@kylinos.cn>
> ---
> block/blk-cgroup-rwstat.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
Reviewed-by: Yu Kuai <yukuai@fygo.io>
--
Thanks,
Kuai
prev parent reply other threads:[~2026-08-03 5:29 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-02 15:04 [PATCH] block/blk-cgroup-rwstat: use data_race() for online test Tao Cui
2026-08-03 5:29 ` Yu Kuai [this message]
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