Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 C7BFD3D7D70; Mon, 17 Aug 2026 15:24:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786980260; cv=none; b=r78jx0wIPG8U54HXx2Bo8/551CRaybuHt8zvga3nfNzm3KUmOziSTVnotfk+DXOg7aUYY6DYQ2wjDhoggro8O1yFmhU6UwXahedSKgaIW/+nUmWzWFzdsQAeQtTpIW6U+Il5SeZnZj8xHwvrlufAzDXPAmQm0RJyVfXm/8mv5/k= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786980260; c=relaxed/simple; bh=sRBm3mOZP9N9wibcN8P/TE16FEyeCQA1hsq6szXKXqs=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=UorEC4a1BKskRBptcZA3Swi13yFtpTnYNbgVapXF1wVk0iohyWqBAZqyHL3aFCPlOiOIq8lDoQAQ4DF6YFrGDLJqnHYVmkse4paYCb5DvBu6P93ombmda8qHdwhXOc66U6cAfZnUnSMcZkBGjSMh0de/EFpdAGn+n6jgMetpgRU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=mjrmauTk; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="mjrmauTk" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2DCFA1F000E9; Mon, 17 Aug 2026 15:24:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1786980259; bh=0cd7GnZKO6nOj8EhUtaIAGg1eMv+/HC4okv4X3lIX1U=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=mjrmauTkO3EilMnghNVo5GccaznClh/quDWdDrzCiJK5RTD4rUPezpbwRL934Xu9R 6oMNoGjMNOtc6ndcG8BOYduHkm1upHbq/Bhb+ZgdhkqfDmLXQx0lHIS+ozVv9CFAZd JkbxC85vmz+cBOfOUiBtfrDiMSd2Vb4RLOeHpZm4= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Zhiling Zou , Ren Wei , =?UTF-8?q?Toke=20H=C3=B8iland-J=C3=B8rgensen?= , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.1 511/609] net/sched: sch_cake: drop WARN_ON(1) for malformed packets in ACK filter Date: Mon, 17 Aug 2026 15:33:27 +0200 Message-ID: <20260817132600.951216181@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260817132543.039278408@linuxfoundation.org> References: <20260817132543.039278408@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Toke Høiland-Jørgensen [ Upstream commit 2a33516f9ef59ad11844d4fc152f889449b5daf3 ] The sch_cake ACK filter parses packets to find the TCP header and filter duplicated ACKs if the flow is backlogged. The parsing code contains a WARN_ON(1) which can be triggered by a malformed IP header in certain cases. Depending on the system configuration, this leads either to either spamming dmesg with warnings, or a panic if panic_on_warn is set. The code already correctly skips the offending packet in the branch that triggers the warning, so the WARN_ON itself doesn't really serve any purpose. So just drop it altogether to avoid the inconvenient side effects. Fixes: 8b7138814f29 ("sch_cake: Add optional ACK filter") Reported-by: Zhiling Zou Reported-by: Ren Wei Signed-off-by: Toke Høiland-Jørgensen Link: https://patch.msgid.link/20260729191417.45665-1-toke@toke.dk Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/sched/sch_cake.c | 1 - 1 file changed, 1 deletion(-) diff --git a/net/sched/sch_cake.c b/net/sched/sch_cake.c index e210a676dc340..1c6f2c623939f 100644 --- a/net/sched/sch_cake.c +++ b/net/sched/sch_cake.c @@ -1281,7 +1281,6 @@ static struct sk_buff *cake_ack_filter(struct cake_sched_data *q, seglen = ntohs(ipv6h_check->payload_len); } else { - WARN_ON(1); /* shouldn't happen */ continue; } -- 2.53.0