From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-yw1-f169.google.com (mail-yw1-f169.google.com [209.85.128.169]) (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 8204840FDA0 for ; Fri, 22 May 2026 13:39:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.169 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779457178; cv=none; b=kD5HbvBeXqJ4vH49cHO8dXE7ds9IXuKQk0BD1+J1zQ/c2RQ6HcjKtMJtwaNpHClOoLiGzvvMkHbs4q4Gy7ltw0Rm0wab8Q8wIGnhhEfQ9o6749pHFQ9RmOhn90qh2Dk5R/5wCsJB364nTEXbrBEosLBsO9Rod+hzjC4W6G6GtrQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779457178; c=relaxed/simple; bh=jDeN2QBMl7BMOZROrFun6LhTmnGtFP6y8AFygNKYfL4=; h=Date:From:To:Cc:Message-ID:In-Reply-To:References:Subject: Mime-Version:Content-Type; b=JRvveVtV700vGOqTJ31XBEwDfvs11M6LYkHptIbZjSnt4Ad/32poNNx3pZXrQ6OyhBhKMXJ/7KCIOp5C3FyXjm5aiOM/J8oqpHIuCDqDA0HMwtEsjaUNJeNvJ3Px6qsz0vO8rb9/8lsuBxx0ndnz8Ib4r2UlagvZ1m5EZpTpEv0= 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=sQnIRaxE; arc=none smtp.client-ip=209.85.128.169 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="sQnIRaxE" Received: by mail-yw1-f169.google.com with SMTP id 00721157ae682-7c0de780bf1so62897097b3.2 for ; Fri, 22 May 2026 06:39:36 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1779457175; x=1780061975; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:subject:references :in-reply-to:message-id:cc:to:from:date:from:to:cc:subject:date :message-id:reply-to; bh=/FlGOyjgzpwLj70dY2yF6Meo00osZD3FjwZeaTgq4XE=; b=sQnIRaxEHl3bpJVceOG2ILeREZJPCxTCmABuDk6pqPZ9agpWkmGVaEN2Bp3vqnyTqH CbjYscADpbO7k7EyhgXFOk3bMkxpHP7o1f3NYQgIk0wJL1hXtJs9QL2m8Ud9eAVs7jmo 7ou3J/07WKtekKgg1GA2V7m3n1chxZDr/4YZj8knHSM0AHxuLsxeUe8WgeJhRDGnni7b X7CXdO4l6bMQY1PPHPGdvXNXCKKSekHRkDY8rjeQqxXDboMApsh07eD44I0VZ5kM6KfN Vkjqy3bquDKIuK+0aLa0IE1H9kXjFg5d5HrSu+kRUUyj7K1IU8Ja5HRrmYJwj4WwoG+8 FpEw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1779457175; x=1780061975; h=content-transfer-encoding:mime-version:subject:references :in-reply-to:message-id:cc:to:from:date:x-gm-gg:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=/FlGOyjgzpwLj70dY2yF6Meo00osZD3FjwZeaTgq4XE=; b=bHOT4m4GotaCBbc5/Qe9cADq9RD32hRqpcJ/MO6SzGxhlq9v2xSdHl9xvLk2a8Nhq3 1cONhIcROX4kTcOy8oR/PpHiY2DW5JrkQ/ciMtSmcHRYKZarNddVK/b0Spn5MQ7PdX+U pMmyAba+aYxo5auFdZltNOl7Q2yY1JGaeM42Vbl2kOt3y9Ci0mIEFTJSqV/mp+Ic4DYy qdjN05E315ZT7r0HoNVj2+e8yNeaCLlJ2lHMut/jwr9xpD1dcMZ1lXyr1icLLvBfIn6o GIZquYhVtyYkClN2Gx51qBsBf1IjrH63mLA9ZEQzNseFkqeN30ngW8DfKKPJisDO6Dot gl2g== X-Forwarded-Encrypted: i=1; AFNElJ/vGd4KahEO3rNoc3KcBEws+yrkwfwWCCRDL7nRDDX4E+wJ7Fvl3ct3Mcme59nkmBWzuj8TWUw=@vger.kernel.org X-Gm-Message-State: AOJu0Yxftr/Zu2VdsjxYqplK+ZLZdRhtnq8rRdVsFzYp2l5I5kN8Qeu5 EwGIdQ3ZTYQ0QrcDRqTLgqMbnRX480sVtk/YVkULrMvvK/Ol6WZTWmn3 X-Gm-Gg: Acq92OG1wrnP4DoWh1yLCzh9qm/Zg8hjUVrXjRqkSRS8bgEO0IEMifXClUGl+Cxbms6 JPY6pi0R52VKKhEi0shP44/UWGC/HBW0SlvBeTSqtrFjyulaPuaNx8Ut3q3S7q6OI2aHKOZqKdA qXNm5EBssERV+zmy+dRRYvyqFIuYUdw1I0jdqIIWkFRqYv3ZPzBMHgob+rCoz0iebTbclvOQ+gV z2dYNtsS+/w2oTHtfjb75H5z2JrkY8Z31JdLLNVhRBCr5yXPjjvC1/0TTYjQSnpB05kQfLKwmBz qfvF7ftzAFHOOYH/Se6qa0+pVxDBHVHLoxLxml/yDCMaixZkJDE0bMmgC4Qwz3sSaDR6hIBT7d7 hnNgkBV0VYkHqyXYLRfQqJsuHQmBLSIa3oqW3YHU6+9v58uFVdnF5rGAN0pNGdWMvfb9plXDzwA jQgkcwK/dVsoCg+NkECwv1PXmpCQOpeaYFOkWEvLBeSE1tq1FADyoBVyWPdY4Vjdk5F8wIgvmCq 5POL24= X-Received: by 2002:a05:690c:9a03:b0:7a3:7ad3:3e9e with SMTP id 00721157ae682-7d33a256b12mr40259867b3.32.1779457175239; Fri, 22 May 2026 06:39:35 -0700 (PDT) Received: from gmail.com (141.139.145.34.bc.googleusercontent.com. [34.145.139.141]) by smtp.gmail.com with ESMTPSA id 00721157ae682-7d38bf2f84esm8032277b3.31.2026.05.22.06.39.34 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 22 May 2026 06:39:34 -0700 (PDT) Date: Fri, 22 May 2026 09:39:34 -0400 From: Willem de Bruijn To: Weiming Shi , netdev@vger.kernel.org Cc: willemdebruijn.kernel@gmail.com, jasowang@redhat.com, pabeni@redhat.com, kuba@kernel.org, edumazet@google.com, dongli.zhang@oracle.com, xmei5@asu.edu, linux-kernel@vger.kernel.org, Weiming Shi Message-ID: In-Reply-To: <20260520160020.375349-2-bestswngs@gmail.com> References: <20260520160020.375349-2-bestswngs@gmail.com> Subject: Re: [PATCH net] tun: free page on short-frame rejection in tun_xdp_one() 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: 7bit Weiming Shi wrote: > tun_xdp_one() returns -EINVAL on a frame shorter than ETH_HLEN without > freeing the page that vhost_net_build_xdp() allocated for it. > tun_sendmsg() discards that -EINVAL and still returns total_len, so > vhost_tx_batch() takes the success path and never frees the page; each > short frame in a batch leaks one page-frag chunk. > > A local process that can open /dev/net/tun and /dev/vhost-net can hit > this path: it attaches a tun/tap device as the vhost-net backend and > feeds TX descriptors whose length minus the virtio-net header is below > ETH_HLEN. Each kick leaks the page-frag chunks for that batch, and a > tight submission loop exhausts host memory and triggers an OOM panic. > Free the page before returning -EINVAL, matching the XDP-program error > path in the same function. > > Fixes: 049584807f1d ("tun: add missing verification for short frame") > Reported-by: Xiang Mei > Assisted-by: Claude:claude-opus-4-7 > Signed-off-by: Weiming Shi Reviewed-by: Willem de Bruijn