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([187.13.206.89]) by smtp.gmail.com with ESMTPSA id 71dfb90a1353d-5c9989fa82esm153202e0c.4.2026.09.15.10.30.12 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 15 Sep 2026 10:30:14 -0700 (PDT) From: Aldo Ariel Panzardo To: Luigi Leonardi , Stefano Garzarella Cc: Bobby Eshleman , davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, horms@kernel.org, virtualization@lists.linux.dev, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, Aldo Ariel Panzardo Subject: Re: [PATCH v2] vsock: ignore empty child namespace mode writes Date: Tue, 15 Sep 2026 14:29:33 -0300 Message-ID: <20260915172952.3174810-1-qwe.aldo@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260915141547.3010692-1-qwe.aldo@gmail.com> References: <20260915141547.3010692-1-qwe.aldo@gmail.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Hi Luigi, Stefano, Thanks for taking a look. Luigi — nothing fancy, I was just reading sysctl handlers and noticed that __vsock_net_mode_string() bails early on a zero-length write without touching new_mode. Since the child mode can only be set once, an empty write that sneaks through locks it with whatever was on the stack. CONFIG_INIT_STACK_ALL_ZERO hides the whole thing, which is probably why nobody hit it in practice. Stefano — yeah, makes more sense to bail before calling the helper at all. Fixed in v3, and I added the CCs I missed. Cheers, Aldo