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Fri, 18 Jul 2025 11:48:53 -0700 (PDT) Date: Fri, 18 Jul 2025 11:48:52 -0700 From: Cong Wang To: Xiang Mei 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 Message-ID: References: <20250717230128.159766-1-xmei5@asu.edu> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline 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 > Signed-off-by: Xiang Mei > Link: https://patch.msgid.link/4a04e0cc-a64b-44e7-9213-2880ed641d77@sabinyo.mountain Reviewed-by: Cong Wang Thanks for the quick fix!