From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wm1-f49.google.com (mail-wm1-f49.google.com [209.85.128.49]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4C95B1EA7EC for ; Thu, 20 Nov 2025 11:16:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.49 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763637388; cv=none; b=P/FpoCkdtEoIpsmqRyxegfLNTOjsCVjP2JA3I4p4MJyx+X8qLKXo+LpuTCDX8KkNIeHemZfiAPO8BYIlE06K/ASGHT9p4LnuOBJlmM1nB93ZUbhc9xKqWxS2AGrbjpoRv/ES3s3CHLERKdVH9GYyeJFr5slgkJgnX8Dxe4eHVAI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763637388; c=relaxed/simple; bh=aaujChFq0aBNtPDtJwu9E+yl31n3maw8a+IjMcDvdgc=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=hPr/i4ewcubec9HwEwcd2CKSsoEFiyOg4i/HDFbS22QrBrPmMPozXlqpEJe9K+fYqJeZZ28UFQhku1NxV0LbKH12teKp4ruXxDLNZ6ctHSacjbLRrsDkgM0J0khvHl0czQ90pAHkGW9oBSQBtf4m2x1NWHFuVuW3I6uGQAGzH4o= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=Cstr9LDO; arc=none smtp.client-ip=209.85.128.49 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="Cstr9LDO" Received: by mail-wm1-f49.google.com with SMTP id 5b1f17b1804b1-477a1c28778so8965165e9.3 for ; Thu, 20 Nov 2025 03:16:27 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1763637386; x=1764242186; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:subject:cc:to:from:date:from:to:cc:subject:date :message-id:reply-to; bh=0OPXfZoq32hCbqwxNyncsVbKNdLZ3Sub0ZLhzzXMtjo=; b=Cstr9LDOZEyibDNHmrlgwZv/kUodflHgjupKdZT7AaNpOXRIyksbd2jGikvCUWiQlq h92nMuj1rxfWVQQgqVo1bqRRjhC3MQrRDH2y7sCjd4TfcHMj8JFZw/uBwDleJp9wsFz4 Uz3k4tuff8DBGsNa3g1mC/RUXZbzUCkCw5VmOz4/qJJQPO8N9X4FKkqnB+HNGNtdVb9F Z9CXDD8W5II8xaTmbK5YlHeE2zoussuM2+FfHBpHcruCKM4hhgjNVQm1zcFEYJTTj/QL nIQN43rtdum/Qv9HAxvaL79rvlBTpJAVoyFcBh36gM8jKEJRiV74Y373mzYamsWYGOQh L/Jw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1763637386; x=1764242186; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:subject:cc:to:from:date:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=0OPXfZoq32hCbqwxNyncsVbKNdLZ3Sub0ZLhzzXMtjo=; b=PqfdED7Np7k3zSK8tHdGPLl8a68RxurNuOdxAc23I9IPwCDCmM9CviajzOcbT2k3N6 Z4kO52Cnn0G27C+ys6Jq5jkI4tmUI+FQ6Dx8ABl4gVNKYZhn+sEF8xzT03NsJ5J9Arv+ VuY+Yor1mWAGd1/AxyaD8eeDeCHBZPz2c6ccoc4BwNWzYUKk1YJDOd6qKEZOI1BYHFjc ZHd+yR86HEeWybtD2I7RxYHS3S7vbHpdfHb4rNFZ/zvU+v5063d3mjY2z/tcBwveEhI+ Mrxy7oqxv50z7hJHkjiAwM2RetLC4t+4pAK5sO64MEojE0mn45IPcXWHos3mb0daRsrX zwPg== X-Forwarded-Encrypted: i=1; AJvYcCW5oNuZ6hQVQ2LXQdcPTCR9UGA2Jav9J3+IoEaez6JZNBFRqIePSF6ti1yWswHf22lEetcecIo=@vger.kernel.org X-Gm-Message-State: AOJu0YxGQopXZX5jP0xCoDR+WUTOKU6Fdx0kj9DGyTdoWCFPZVGStXR1 x+x6zRofconfvO1TJ+MXcTttil0rtes2bnelEgg318fFMqXl/aupKq00 X-Gm-Gg: ASbGncuP+ZsqIqrAAJgEmu7HaaJG0Bzq+RJRkGvJermS5gGB1iV3VPzxCgmjc0leYkM luLhzDjbK3QRvwYSiSQhcvpMcZ7TyCmSTlEnX71hXjLsphwhAI/03fngMjRp4Bbl9R12Wk9vXXk e7PbDhgjKWfKlPHt5SXFza/r6BZ7OvwFZRW8WRFZXJacpQDHU+p41HVF7YvY39E9kRibJFgwSAH E+lMGBmeROYwv8rXZxUE78giUXVf812qEiBnuonongf60QM9IIxtCBQVIeuvLBXhH6J/jn/41br aqQ2r8aToGNQOnYJ+X+zRHSiRntplubuyaVz6tJwi9huuxs+NWSa0n2eVrhzS69/2nds6+nLMPR lGN6nrifVoEO8iuCi7ML125BQSeqTFevfLRKSYHeAAw1nCmSmSQKPU7g1di2iLSxrZUQyY4z+3G cdY0/mI7rLU/e4JRhewneUiGynVmqJTd7ReujYIO+amHpPW06x+kFT X-Google-Smtp-Source: AGHT+IFZB29IrybraSPGQhV7roEItbkZW/1Rvxj8aVil7QNoLoeVbtGz5PzkfltFhZGqHiCqn2Q5ow== X-Received: by 2002:a05:600c:3115:b0:477:89d5:fdac with SMTP id 5b1f17b1804b1-477b8a9f9camr28349905e9.31.1763637385245; Thu, 20 Nov 2025 03:16:25 -0800 (PST) Received: from pumpkin (82-69-66-36.dsl.in-addr.zen.co.uk. [82.69.66.36]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-477a973dbabsm64908285e9.3.2025.11.20.03.16.24 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 20 Nov 2025 03:16:24 -0800 (PST) Date: Thu, 20 Nov 2025 11:16:23 +0000 From: David Laight To: bot+bpf-ci@kernel.org Cc: linux-kernel@vger.kernel.org, netdev@vger.kernel.org, dsahern@kernel.org, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, ast@kernel.org, andrii@kernel.org, daniel@iogearbox.net, martin.lau@kernel.org, eddyz87@gmail.com, yonghong.song@linux.dev, clm@meta.com, ihor.solodrai@linux.dev Subject: Re: [PATCH 09/44] ipv6: __ip6_append_data() don't abuse max_t() casts Message-ID: <20251120111623.44ebfae7@pumpkin> In-Reply-To: References: <20251119224140.8616-10-david.laight.linux@gmail.com> X-Mailer: Claws Mail 4.1.1 (GTK 3.24.38; arm-unknown-linux-gnueabihf) 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-Transfer-Encoding: 7bit On Thu, 20 Nov 2025 00:32:34 +0000 (UTC) bot+bpf-ci@kernel.org wrote: > > diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c > > index f904739e9..6fecf2f2c 100644 > > --- a/net/ipv6/ip6_output.c > > +++ b/net/ipv6/ip6_output.c > > @@ -1440,7 +1440,7 @@ static int __ip6_append_data(struct sock *sk, > > struct sk_buff *skb, *skb_prev = NULL; > > struct inet_cork *cork = &cork_full->base; > > struct flowi6 *fl6 = &cork_full->fl.u.ip6; > > - unsigned int maxfraglen, fragheaderlen, mtu, orig_mtu, pmtu; > > + unsigned int maxfraglen, fragheaderlen, mtu, orig_mtu; > > [ ... ] > > > @@ -1504,9 +1504,10 @@ static int __ip6_append_data(struct sock *sk, > > maxnonfragsize = mtu; > > > > if (cork->length + length > maxnonfragsize - headersize) { > > + int pmtu; > > emsgsize: > > - pmtu = max_t(int, mtu - headersize + sizeof(struct ipv6hdr), 0); > > - ipv6_local_error(sk, EMSGSIZE, fl6, pmtu); > > + pmtu = mtu - headersize + (int)sizeof(struct ipv6hdr); > > + ipv6_local_error(sk, EMSGSIZE, fl6, max(pmtu, 0)); > > return -EMSGSIZE; > > } > > Can the variable pmtu be used uninitialized here? If your AI bot doesn't understand code don't run it. David > > When reaching the emsgsize label via goto statements from earlier in > __ip6_append_data() (the checks at lines around mtu <= fragheaderlen, > headersize + transhdrlen > mtu, and the dontfrag check), the int pmtu > declaration is skipped. This leaves pmtu uninitialized when it's used > in the calculation that's passed to ipv6_local_error(). > > > --- > AI reviewed your patch. Please fix the bug or email reply why it's not a bug. > See: https://github.com/kernel-patches/vmtest/blob/master/ci/claude/README.md > > CI run summary: https://github.com/kernel-patches/bpf/actions/runs/19519124312