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From: Tejun Heo <tj@kernel.org>
To: Guopeng Zhang <guopeng.zhang@linux.dev>
Cc: Johannes Weiner <hannes@cmpxchg.org>, =?UTF-8?Q?Michal_Koutn=C3=BD?= <mkoutny@suse.com>, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, Guopeng Zhang <zhangguopeng@kylinos.cn>, Tao Cui <cui.tao@linux.dev>
Subject: Re: [PATCH] cgroup: Use READ_ONCE() for task->flags in task_css_set_check()
In-Reply-To: <20260623022946.525885-1-guopeng.zhang@linux.dev>
References: <20260623022946.525885-1-guopeng.zhang@linux.dev>
Message-Id: <20260624202644.877fae40488c@kernel.org>
Date: Wed, 24 Jun 2026 10:26:44 -1000
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On Tue, Jun 23, 2026 at 10:29:46AM +0800, Guopeng Zhang wrote:
> -		((task)->flags & PF_EXITING) || (__c))
> +		(READ_ONCE((task)->flags) & PF_EXITING) || (__c))

This only feeds the CONFIG_PROVE_RCU lockdep predicate, so it's a
diagnostic-only read. tools/memory-model/Documentation/access-marking.txt
recommends data_race() over READ_ONCE() for those:

	(data_race((task)->flags) & PF_EXITING) || (__c))

Please update the changelog to match.

Thanks.