From: Cong Wang <xiyou.wangcong@gmail.com>
To: Xiang Mei <xmei5@asu.edu>
Cc: dan.carpenter@linaro.org, netdev@vger.kernel.org
Subject: Re: [PATCH v1] net/sched: sch_qfq: Avoid triggering might_sleep in atomic context in qfq_delete_class
Date: Fri, 18 Jul 2025 11:48:52 -0700 [thread overview]
Message-ID: <aHqXFDrL/r2UWWCP@pop-os.localdomain> (raw)
In-Reply-To: <20250717230128.159766-1-xmei5@asu.edu>
On Thu, Jul 17, 2025 at 04:01:28PM -0700, Xiang Mei wrote:
> might_sleep could be trigger in the atomic context in qfq_delete_class.
>
> qfq_destroy_class was moved into atomic context locked
> by sch_tree_lock to avoid a race condition bug on
> qfq_aggregate. However, might_sleep could be triggered by
> qfq_destroy_class, which introduced sleeping in atomic context (path:
> qfq_destroy_class->qdisc_put->__qdisc_destroy->lockdep_unregister_key
> ->might_sleep).
>
> Considering the race is on the qfq_aggregate objects, keeping
> qfq_rm_from_agg in the lock but moving the left part out can solve
> this issue.
>
> Fixes: 5e28d5a3f774 ("net/sched: sch_qfq: Fix race condition on qfq_aggregate")
> Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
> Signed-off-by: Xiang Mei <xmei5@asu.edu>
> Link: https://patch.msgid.link/4a04e0cc-a64b-44e7-9213-2880ed641d77@sabinyo.mountain
Reviewed-by: Cong Wang <xiyou.wangcong@gmail.com>
Thanks for the quick fix!
next prev parent reply other threads:[~2025-07-18 18:48 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-07-17 23:01 [PATCH v1] net/sched: sch_qfq: Avoid triggering might_sleep in atomic context in qfq_delete_class Xiang Mei
2025-07-18 18:48 ` Cong Wang [this message]
2025-07-18 19:43 ` Dan Carpenter
2025-07-18 21:11 ` Xiang Mei
2025-07-22 10:20 ` patchwork-bot+netdevbpf
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