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[83.233.221.133]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-c46bd7984f5sm417942766b.77.2026.10.27.02.27.24 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 27 Oct 2026 02:27:25 -0700 (PDT) From: Yongzhao Chen To: netdev-bot+sinfo@kernel.org Cc: netdev@vger.kernel.org, Christian Marangi , Andrew Lunn , Vladimir Oltean , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , Russell King , Florian Fainelli , linux-kernel@vger.kernel.org, Ziyang Huang Subject: Re: [PATCH net v7] net: dsa: qca8k: preserve port state across MTU changes Date: Tue, 27 Oct 2026 10:27:18 +0100 Message-ID: <20261027092718.266370-1-yongzhao.derek@gmail.com> X-Mailer: git-send-email 2.55.0.windows.5 In-Reply-To: <179268501671.3290.6623232109527554630@kernel.org> References: <20261022155837.760-1-yongzhao.derek@gmail.com> <179268501671.3290.6623232109527554630@kernel.org> X-Mailing-List: netdev@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit On Thu, 22 Oct 2026 16:03:36 +0000 netdev-bot+sinfo@kernel.org wrote: > - How the issue was discovered, e.g. hit in production, hit during > development, syzbot report, manual code inspection, LLM or static > analysis tool scan. The original problem was found during development, not in production. While preparing the net-next RFC v2 [1], which extended the CPU MAC pause in qca8k_port_change_mtu() to internal CPU ports, I asked an LLM agent for an adversarial review of that change. The review found that the existing sequence re-enables the port 0 and 6 MACs after phylink has taken the link down, and that phylink callbacks can run during the update. The problems fixed in v6 and v7 were reported by Sashiko on v5 and v6. I reproduced them, and the original problem with the unpatched code, in a userspace harness that compiles the driver and DSA MTU functions with mocked register access. None of them has been reproduced on hardware, and v7 has not been tested on hardware. Sashiko's review of v7 is a separate question and is still open. [1] https://lore.kernel.org/netdev/20260922202653.1153-1-yongzhao.derek@gmail.com/ Thanks, Yongzhao Chen