From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 813A94A0C for ; Thu, 27 Nov 2025 23:36:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764286606; cv=none; b=un0vCoXKFD4csPJB83FIeUaNzjF2+2HTuEosSc0qPLxB10SKIE6z16oewdP4x4OkUvfz5EgQfeJK8tZGJG/6RjvC9adhr7zMbOcbH+3NzFqoI/vAEcFOL1csLf/SUmZzRAy10Z0ZhfRnKzZSIDGOcTj0GMekHrajBlYWBPnnhKg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764286606; c=relaxed/simple; bh=34KozKoOVCmT+6fnS1OOQMxNpW5m8bk9dYmhP2vKwYU=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=GQH0s/kuIe1fqGMuM1ZqtW/Io2Wnb0JexAdq8YWbJfmeVXUbDzVL+zzZrcgTBvb1QwAynS1eE247zJoHkfImf5SdPIBi0t50uGIg4dhiF7dG9vnEOg9XOOwBmmJWNSOG45pv8gaBPPvnpleJWagQDBJnp85lN75gl5qCVSNOYq8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=GM7O+sLH; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="GM7O+sLH" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A52D5C4CEF8; Thu, 27 Nov 2025 23:36:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1764286606; bh=34KozKoOVCmT+6fnS1OOQMxNpW5m8bk9dYmhP2vKwYU=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=GM7O+sLHQe2TWcnufenIMMz9qPJHizbr/IzJAQqhFAVwpfiUENzpz/7cZs2iH94FZ 9B1nMlScIz9crUcUbv4MLW0yJynaZS7PRPc1RR9gmnioyBA4aLBZGKy+IuGj8zaraC ct/0Nh4Rj+5t+JtrFX8mBWHLeLLnRNTKu//9+Gd3iRcsAh5V99TrBuBMF2tjPqzAxb RzAXfdQ982OYeAptmqCV7gC/TsASXjZz9mfF9AwEkkKVOwFoKjXpmvvbxvvXd2VcpS c2tFw0oSGv+32usdJKwUqpCBe7Osux7Z1mDSPDstuDbr/1x4OwCduqPSDgv0F08iHC g6H/CteAL7q+Q== Date: Thu, 27 Nov 2025 15:36:44 -0800 From: Jakub Kicinski To: Xiang Mei Cc: security@kernel.org, netdev@vger.kernel.org, toke@toke.dk, xiyou.wangcong@gmail.com, cake@lists.bufferbloat.net, bestswngs@gmail.com Subject: Re: [PATCH net v7 1/2] net/sched: sch_cake: Fix incorrect qlen reduction in cake_drop Message-ID: <20251127153644.55ef4796@kernel.org> In-Reply-To: <20251126194513.3984722-1-xmei5@asu.edu> References: <20251126194513.3984722-1-xmei5@asu.edu> 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 Wed, 26 Nov 2025 12:45:12 -0700 Xiang Mei wrote: > In cake_drop(), qdisc_tree_reduce_backlog() is used to update the qlen > and backlog of the qdisc hierarchy. Its caller, cake_enqueue(), assumes > that the parent qdisc will enqueue the current packet. However, this > assumption breaks when cake_enqueue() returns NET_XMIT_CN: the parent > qdisc stops enqueuing current packet, leaving the tree qlen/backlog > accounting inconsistent. This mismatch can lead to a NULL dereference > (e.g., when the parent Qdisc is qfq_qdisc). This series does not apply, please rebase on netdev/net/main. -- pw-bot: cr