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=-8.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 6F247C48BE6 for ; Fri, 11 Jun 2021 10:04:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4F5926124C for ; Fri, 11 Jun 2021 10:04:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231175AbhFKKGj (ORCPT ); Fri, 11 Jun 2021 06:06:39 -0400 Received: from so254-9.mailgun.net ([198.61.254.9]:25841 "EHLO so254-9.mailgun.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229969AbhFKKGh (ORCPT ); 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Fri, 11 Jun 2021 10:03:45 +0000 (UTC) Received: from tykki.adurom.net (tynnyri.adurom.net [51.15.11.48]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) (Authenticated sender: kvalo) by smtp.codeaurora.org (Postfix) with ESMTPSA id A0C4EC433F1; Fri, 11 Jun 2021 10:03:41 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org A0C4EC433F1 Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; spf=fail smtp.mailfrom=kvalo@codeaurora.org Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: Re: [PATCH 5.13] mwifiex: bring down link before deleting interface From: Kalle Valo In-Reply-To: <20210515024227.2159311-1-briannorris@chromium.org> References: <20210515024227.2159311-1-briannorris@chromium.org> To: Brian Norris Cc: linux-wireless@vger.kernel.org, , Ganapathi Bhat , Sharvari Harisangam , Amitkumar Karwar , Xinming Hu , Brian Norris , stable@vger.kernel.org, Maximilian Luz , dave@bewaar.me, Johannes Berg User-Agent: pwcli/0.1.0-git (https://github.com/kvalo/pwcli/) Python/3.7.3 Message-Id: <20210611100345.D83C2C433D3@smtp.codeaurora.org> Date: Fri, 11 Jun 2021 10:03:45 +0000 (UTC) Precedence: bulk List-ID: X-Mailing-List: linux-wireless@vger.kernel.org Brian Norris wrote: > We can deadlock when rmmod'ing the driver or going through firmware > reset, because the cfg80211_unregister_wdev() has to bring down the link > for us, ... which then grab the same wiphy lock. > > nl80211_del_interface() already handles a very similar case, with a nice > description: > > /* > * We hold RTNL, so this is safe, without RTNL opencount cannot > * reach 0, and thus the rdev cannot be deleted. > * > * We need to do it for the dev_close(), since that will call > * the netdev notifiers, and we need to acquire the mutex there > * but don't know if we get there from here or from some other > * place (e.g. "ip link set ... down"). > */ > mutex_unlock(&rdev->wiphy.mtx); > ... > > Do similarly for mwifiex teardown, by ensuring we bring the link down > first. > > Sample deadlock trace: > > [ 247.103516] INFO: task rmmod:2119 blocked for more than 123 seconds. > [ 247.110630] Not tainted 5.12.4 #5 > [ 247.115796] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. > [ 247.124557] task:rmmod state:D stack: 0 pid: 2119 ppid: 2114 flags:0x00400208 > [ 247.133905] Call trace: > [ 247.136644] __switch_to+0x130/0x170 > [ 247.140643] __schedule+0x714/0xa0c > [ 247.144548] schedule_preempt_disabled+0x88/0xf4 > [ 247.149714] __mutex_lock_common+0x43c/0x750 > [ 247.154496] mutex_lock_nested+0x5c/0x68 > [ 247.158884] cfg80211_netdev_notifier_call+0x280/0x4e0 [cfg80211] > [ 247.165769] raw_notifier_call_chain+0x4c/0x78 > [ 247.170742] call_netdevice_notifiers_info+0x68/0xa4 > [ 247.176305] __dev_close_many+0x7c/0x138 > [ 247.180693] dev_close_many+0x7c/0x10c > [ 247.184893] unregister_netdevice_many+0xfc/0x654 > [ 247.190158] unregister_netdevice_queue+0xb4/0xe0 > [ 247.195424] _cfg80211_unregister_wdev+0xa4/0x204 [cfg80211] > [ 247.201816] cfg80211_unregister_wdev+0x20/0x2c [cfg80211] > [ 247.208016] mwifiex_del_virtual_intf+0xc8/0x188 [mwifiex] > [ 247.214174] mwifiex_uninit_sw+0x158/0x1b0 [mwifiex] > [ 247.219747] mwifiex_remove_card+0x38/0xa0 [mwifiex] > [ 247.225316] mwifiex_pcie_remove+0xd0/0xe0 [mwifiex_pcie] > [ 247.231451] pci_device_remove+0x50/0xe0 > [ 247.235849] device_release_driver_internal+0x110/0x1b0 > [ 247.241701] driver_detach+0x5c/0x9c > [ 247.245704] bus_remove_driver+0x84/0xb8 > [ 247.250095] driver_unregister+0x3c/0x60 > [ 247.254486] pci_unregister_driver+0x2c/0x90 > [ 247.259267] cleanup_module+0x18/0xcdc [mwifiex_pcie] > > Fixes: a05829a7222e ("cfg80211: avoid holding the RTNL when calling the driver") > Cc: stable@vger.kernel.org > Link: https://lore.kernel.org/linux-wireless/98392296-40ee-6300-369c-32e16cff3725@gmail.com/ > Link: https://lore.kernel.org/linux-wireless/ab4d00ce52f32bd8e45ad0448a44737e@bewaar.me/ > Reported-by: Maximilian Luz > Reported-by: dave@bewaar.me > Cc: Johannes Berg > Signed-off-by: Brian Norris > Tested-by: Maximilian Luz > Tested-by: Dave Olsthoorn Patch applied to wireless-drivers.git, thanks. 1f9482aa8d41 mwifiex: bring down link before deleting interface -- https://patchwork.kernel.org/project/linux-wireless/patch/20210515024227.2159311-1-briannorris@chromium.org/ https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches