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[209.147.138.224]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-74ce429b6a3sm9277965b3a.126.2025.07.07.16.42.43 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 07 Jul 2025 16:42:44 -0700 (PDT) Date: Mon, 7 Jul 2025 16:42:42 -0700 From: Xiang Mei To: Jakub Kicinski Cc: xiyou.wangcong@gmail.com, netdev@vger.kernel.org, gregkh@linuxfoundation.org, jhs@mojatatu.com, jiri@resnulli.us, security@kernel.org Subject: Re: [PATCH v1] net/sched: sch_qfq: Fix race condition on qfq_aggregate Message-ID: References: <20250705223958.4079242-1-xmei5@asu.edu> <20250707105833.0c6926dc@kernel.org> 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: <20250707105833.0c6926dc@kernel.org> On Mon, Jul 07, 2025 at 10:58:33AM -0700, Jakub Kicinski wrote: > On Sat, 5 Jul 2025 15:39:58 -0700 Xiang Mei wrote: > > A race condition can occur when 'agg' is modified in qfq_change_agg > > (called during qfq_enqueue) while other threads access it > > concurrently. For example, qfq_dump_class may trigger a NULL > > dereference, and qfq_delete_class may cause a use-after-free. > > Please don't post patches in reply to threads. Thanks for the reminder. I'll remember it. > Add a link to the thread using the Link: marker instead. > You're also missing a Fixes tag here. Also, thanks for the "Fixes" tag suggestion. I read some documents introducing the Fixes tag, but I find it hard to find a Fixes commit since it's a design issue (lack of lock implementation on agg).