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=-4.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,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 62E79C433B4 for ; Fri, 14 May 2021 13:46:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 32C0861355 for ; Fri, 14 May 2021 13:46:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231447AbhENNr1 (ORCPT ); Fri, 14 May 2021 09:47:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42748 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231196AbhENNr0 (ORCPT ); Fri, 14 May 2021 09:47:26 -0400 Received: from mail-wr1-x435.google.com (mail-wr1-x435.google.com [IPv6:2a00:1450:4864:20::435]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 337DCC061574; Fri, 14 May 2021 06:46:14 -0700 (PDT) Received: by mail-wr1-x435.google.com with SMTP id a4so30114916wrr.2; Fri, 14 May 2021 06:46:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:from:to:cc:references:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=Ymmwx+IZNZPtmksX0LXS0g42bC5sLEqQJ+dxtmdHYAA=; b=L1hlMocshLK/8w3hl4DzeGupCK4WzLVF0cSbeTtoaPnsXJDk+135j/93Y9dCVhM4hO zdyJXwNH2byhNXJIRIDSOmpFYaPUX2HHAz7eYkc02FCylvuwNVJgVHt/ok99/hAshpUI 00WJofJl4eCM2gAJLOOcONh6tJL9+nxb89V8K2cB8g/YfV1CoPnFKXvNys/czaOzRVgN u9RnA5qiEjai6yNuTXp655zcwP1EHR2hBW/oup5mJ+oq5NkJ9V5H2KTFqZbu8Kkok6rw ZJal0ErO1X8YRJx8+hqvg9KRQpjreGgrEe12GNK6h3utAieKw7fCxPdZxojGp1MGNmBm tHog== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:from:to:cc:references:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=Ymmwx+IZNZPtmksX0LXS0g42bC5sLEqQJ+dxtmdHYAA=; b=KV/COAIxw4jKIlIdx9U06PzJ2Edga0ouHs6hiN/gZ4xloZWMK2qVxrClDBN7+8BuMv xs0Z8SZ1ZXMO18x1QkSeQam6KjCENGTg20/+HCLZ+AKw0wd0p3Y5i+xRz3po5xi22/45 d+xK5uqecuTorirvFvD/YB+NkvYcteAvZAShmWpvtkutIDBlPEhzhsdngIRoMNaSqLb9 uqWWIs+maPS0Rl/wq2KukXy9zWhM33c/H7wksGvpE5IhbryYbxMcGo0eXFQKfp/KSmck o8GbveMG+cPq7wIdeBOy669pkJdMRygkwVImw/lQOFodr1pRB9bUmBaAYbzR6yWFXuNm 30Hw== X-Gm-Message-State: AOAM530W04q1MAa9rFtxG0klQJeFdUTpCc1Yqo29RLdW7anCmRCpeAmt wTFMzhXXddYtEloIVC+7d5w= X-Google-Smtp-Source: ABdhPJw3flR6Q8XtcnS7uEUlO2rb16YVbcmlkDfIxQUCIWFEz+R8GpKG3A679HYO9Kz5vKY7yn8uXg== X-Received: by 2002:adf:ebc4:: with SMTP id v4mr259508wrn.217.1620999973011; Fri, 14 May 2021 06:46:13 -0700 (PDT) Received: from [192.168.2.202] (pd9e5a369.dip0.t-ipconnect.de. [217.229.163.105]) by smtp.gmail.com with ESMTPSA id q12sm6626954wrx.17.2021.05.14.06.46.11 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 14 May 2021 06:46:12 -0700 (PDT) Subject: Re: [BUG] Deadlock in _cfg80211_unregister_wdev() From: Maximilian Luz To: Johannes Berg , linux-wireless@vger.kernel.org Cc: Marek Szyprowski , Kalle Valo , "David S. Miller" , Jakub Kicinski , netdev@vger.kernel.org, Amitkumar Karwar , Ganapathi Bhat , Xinming Hu , dave@bewaar.me References: <98392296-40ee-6300-369c-32e16cff3725@gmail.com> Message-ID: Date: Fri, 14 May 2021 15:46:11 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.10.1 MIME-Version: 1.0 In-Reply-To: <98392296-40ee-6300-369c-32e16cff3725@gmail.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-wireless@vger.kernel.org On 5/14/21 1:07 AM, Maximilian Luz wrote: > Following commit a05829a7222e ("cfg80211: avoid holding the RTNL when > calling the driver"), the mwifiex_pcie module fails to unload. This also > prevents the device from rebooting / shutting down. > > Attempting to unload the module produces the log pasted below. Upon > further investigation, this looks like a deadlock inside > _cfg80211_unregister_wdev(): > > - According to [1], this function expects the rdev->wiphy.mtx to be >   held. > - Down the line, this function (through some indirections, see third >   trace in log below) calls call_netdevice_notifiers(NETDEV_GOING_DOWN, >   ...) [2]. > - One of the registered notifiers seems to be >   cfg80211_netdev_notifier_call(), which attempts to lock >   rdev->wiphy.mtx again [3], completing the deadlock. Looks like the underlying issue also leads to https://lore.kernel.org/linux-wireless/ab4d00ce52f32bd8e45ad0448a44737e@bewaar.me/ Regards, Max