From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0022CC433ED for ; Tue, 27 Apr 2021 07:43:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C845B61026 for ; Tue, 27 Apr 2021 07:43:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235170AbhD0HoT (ORCPT ); Tue, 27 Apr 2021 03:44:19 -0400 Received: from helcar.hmeau.com ([216.24.177.18]:54430 "EHLO deadmen.hmeau.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234964AbhD0HoP (ORCPT ); Tue, 27 Apr 2021 03:44:15 -0400 Received: from gondobar.mordor.me.apana.org.au ([192.168.128.4] helo=gondobar) by deadmen.hmeau.com with esmtp (Exim 4.89 #2 (Debian)) id 1lbINQ-0008Em-Br; Tue, 27 Apr 2021 15:43:24 +0800 Received: from herbert by gondobar with local (Exim 4.89) (envelope-from ) id 1lbINN-0002DQ-QE; Tue, 27 Apr 2021 15:43:21 +0800 Date: Tue, 27 Apr 2021 15:43:21 +0800 From: Herbert Xu To: Linus Torvalds Cc: harald@skogtun.org, johannes@sipsolutions.net, linux-kernel@vger.kernel.org, netdev@vger.kernel.org Subject: Re: [BISECTED] 5.12 hangs at reboot Message-ID: <20210427074321.callv22dm4drb2jn@gondor.apana.org.au> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Newsgroups: apana.lists.os.linux.kernel Organization: Core User-Agent: NeoMutt/20170113 (1.7.2) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Linus Torvalds wrote: > > At a guess, there is some other sequence that takes the rtnl lock, and > then takes the wiphy_lock inside of it, and we have a ABBA deadlock. The most common cause of these lockups is a stray reference on some kind of a network object, e.g., a socket or some such. This then causes the underlying network device to be reference counted and triggers a lock-up if that network device needs to be removed. > I _hate_ that stupid rtnl lock. It's come up before. Several times. > It's probably the most broken lock in the kernel. Yes, it's the networking equivalent of the BKL. Cheers, -- Email: Herbert Xu Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt