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Tue, 15 Jul 2025 11:13:24 -0700 (PDT) Date: Tue, 15 Jul 2025 11:13:23 -0700 From: Cong Wang To: Xiang Mei Cc: Jakub Kicinski , netdev@vger.kernel.org, gregkh@linuxfoundation.org, jhs@mojatatu.com, jiri@resnulli.us, security@kernel.org Subject: Re: [PATCH v3] net/sched: sch_qfq: Fix race condition on qfq_aggregate Message-ID: References: <20250710100942.1274194-1-xmei5@asu.edu> <20250714153223.5137cafe@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: On Mon, Jul 14, 2025 at 05:09:42PM -0700, Xiang Mei wrote: > > Here is more information no how I tested: > > 1) I ran `python3 ./tdc.py -f ./tc-tests/infra/qdiscs.json -e 5e6d` 100 > times > 2) The KASAN is enabled, and my patch is on it > 3) All 100 results show `ok 1 5e6d - Test QFQ's enqueue reentrant behaviour > with netem` without any crashing in dmesg > > I may need more information to trace this crash. Now I figured out why... It is all because of I used a wrong vmlinux to test this. Although I switched to vanilla -net branch, I forgot to rebuild the vmlinux which was still the one with my netem patches. And I just saw "netem duplicate 100%" in test case 5e6d, now it explains everything. Appologize for my stupid mistake here. I think it is clearly caused by my netem duplication patch (although the fix is not necessarily there). I will take care of this in my netem patchset. Sorry for the noise.