From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.itouring.de (mail.itouring.de [85.10.202.141]) (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 D2321263C9B; Mon, 21 Apr 2025 11:51:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=85.10.202.141 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745236265; cv=none; b=LTnEe5S3H1OohT98SGfKliIQlA4GViJp/TUi/rin7X/FdKgeHRKuEjc1B4aLYTNtN8HYnP+aga9AYIzSGua2FXAz9Sz0UdtP6SBRcMjGbVcD/OfiKjfB/ePG3zOFy+158pqlwXsyyvCbc4pUnp7mRAuqfLMOsCWKKQHy4AZKgas= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745236265; c=relaxed/simple; bh=xLSeYSn0wxwfBOXloKBUUIaklM5Lf3N9jYHxYSNill4=; h=Subject:To:References:From:Message-ID:Date:MIME-Version: In-Reply-To:Content-Type; b=ExoaqWIgKPGmeTXXm+MffvwG8lQRQmqYF/0E5bZoLgPd+0cWAvQ+peRVnoy3jInZsbyNihQ5bgne06Sf7y/7PQK5eZpV6eI4F8EiLp98F/Cozrjm+tnj9cULvzsCL/mszel8x1vF4yGAwwoS4ZdjcvxKPyJATZ+Glxju0/2Q/eg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=applied-asynchrony.com; spf=pass smtp.mailfrom=applied-asynchrony.com; arc=none smtp.client-ip=85.10.202.141 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=applied-asynchrony.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=applied-asynchrony.com Received: from tux.applied-asynchrony.com (p5b07e9b7.dip0.t-ipconnect.de [91.7.233.183]) by mail.itouring.de (Postfix) with ESMTPSA id 670791255FA; Mon, 21 Apr 2025 13:50:53 +0200 (CEST) Received: from [192.168.100.223] (ragnarok.applied-asynchrony.com [192.168.100.223]) by tux.applied-asynchrony.com (Postfix) with ESMTP id 32042601893B6; Mon, 21 Apr 2025 13:50:52 +0200 (CEST) Subject: Re: [REGRESSION] 6.14.3 panic - kernel NULL pointer dereference in htb_dequeue To: "Alan J. Wylie" , Jamal Hadi Salim , regressions@lists.linux.dev, Cong Wang , Jiri Pirko , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Octavian Purdila , =?UTF-8?Q?Toke_H=c3=b8iland-J=c3=b8rgensen?= , stable@vger.kernel.org References: <20250421104019.7880108d@frodo.int.wylie.me.uk> From: =?UTF-8?Q?Holger_Hoffst=c3=a4tte?= Organization: Applied Asynchrony, Inc. Message-ID: <6fa68b02-cf82-aeca-56e6-e3b8565b22f4@applied-asynchrony.com> Date: Mon, 21 Apr 2025 13:50:52 +0200 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 In-Reply-To: <20250421104019.7880108d@frodo.int.wylie.me.uk> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit On 2025-04-21 11:40, Alan J. Wylie wrote: > #regzbot introduced: 6.14.2..6.14.3 > > Since 6.14.3 I have been seeing random panics, all in htb_dequeue. > 6.14.2 was fine. 6.14.3 contains: "codel: remove sch->q.qlen check before qdisc_tree_reduce_backlog()" aka https://web.git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/net/sched?h=linux-6.14.y&id=a57fe60ef4cf96bfbb6b58397ec28bdb5a5c6b31 Is your HTB backed by fq_codel by any chance? If so, try either reverting the above or adding: "sch_htb: make htb_qlen_notify() idempotent" aka https://web.git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=5ba8b837b522d7051ef81bacf3d95383ff8edce5 which was successfully not added to 6.14.3, along with the rest of the series: https://lore.kernel.org/all/20250403211033.166059-2-xiyou.wangcong@gmail.com/ Hope this helps. I am running fq_codel without issue but not behind htb. cheers Holger