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 3F8683911DC; Mon, 17 Aug 2026 14:47:19 +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=1786978040; cv=none; b=r+JzeYsxrECPes7v6z/0N0ChnhFkvwUHQxcHSn88EcUx4mIqh80ZzVQ3m9jz1QitlNgiAJbsI9p1ivievBQcwfq4sPY6yZRN0UiWfS2UhOiM12MHT18QmOyhaFPPXMQYroCAIwT8/1q8xxzRfbfgLr4mVZ8Tp0ITLZ0iKGCJwoY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786978040; c=relaxed/simple; bh=C8qbGyR+GU2MUO2Oi5RDOAtYZqz/rYaHhwB1KxXSZYI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=LcSYTgxiWt+DOsZZ6Gno1eQigXeJK5XCTZq2Yi9vzNQmyNNtCcAN+EFks9QbsZlvvdCGGLyUgiaTmERcnG2E2CohOrC471ZDqwcbJNLq/21Uh3wkC56NxEoN8oVIxvi4NGhMRs69UzBoQFS4JYFG0D83RdLQE07F2mmyaSHCO34= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=qY/s1XZq; 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="qY/s1XZq" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 976041F000E9; Mon, 17 Aug 2026 14:47:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1786978039; bh=xNpq8aOC64Yk5KN232/ZMrVIBl8sXAjV0KpjArkbhCQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=qY/s1XZqEG8XpIqUWFbVNjh3PSQ97akOKZICjqqUCqhsMW/0x8Eny4wGMZLaz/+5d v0lSnoneGrnPZl3B2gOjQVwiTnnq7+0K9ycAOY/aA3U1UC2EzN7rynZ348BhL/SsRf WLANp3r3yf1q+TGWO7wtJCbf5nP3G2MYMl0jzJIo= 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 6.12 041/181] net/sched: sch_cake: drop WARN_ON(1) for malformed packets in ACK filter Date: Mon, 17 Aug 2026 15:32:15 +0200 Message-ID: <20260817132537.001351925@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260817132535.394764707@linuxfoundation.org> References: <20260817132535.394764707@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 6.12-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 2f33739036bb1..43908ec231696 100644 --- a/net/sched/sch_cake.c +++ b/net/sched/sch_cake.c @@ -1265,7 +1265,6 @@ 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