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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3BB4BC433FE for ; Wed, 16 Nov 2022 09:27:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232503AbiKPJ1x (ORCPT ); Wed, 16 Nov 2022 04:27:53 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49890 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231622AbiKPJ1u (ORCPT ); Wed, 16 Nov 2022 04:27:50 -0500 Received: from www262.sakura.ne.jp (www262.sakura.ne.jp [202.181.97.72]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5658A1CC for ; Wed, 16 Nov 2022 01:27:49 -0800 (PST) Received: from fsav312.sakura.ne.jp (fsav312.sakura.ne.jp [153.120.85.143]) by www262.sakura.ne.jp (8.15.2/8.15.2) with ESMTP id 2AG9RkBP048011; Wed, 16 Nov 2022 18:27:47 +0900 (JST) (envelope-from penguin-kernel@I-love.SAKURA.ne.jp) Received: from www262.sakura.ne.jp (202.181.97.72) by fsav312.sakura.ne.jp (F-Secure/fsigk_smtp/550/fsav312.sakura.ne.jp); Wed, 16 Nov 2022 18:27:46 +0900 (JST) X-Virus-Status: clean(F-Secure/fsigk_smtp/550/fsav312.sakura.ne.jp) Received: from [192.168.1.9] (M106072142033.v4.enabler.ne.jp [106.72.142.33]) (authenticated bits=0) by www262.sakura.ne.jp (8.15.2/8.15.2) with ESMTPSA id 2AG9RkVe048008 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NO); Wed, 16 Nov 2022 18:27:46 +0900 (JST) (envelope-from penguin-kernel@I-love.SAKURA.ne.jp) Message-ID: <8a3964bd-41fa-5179-1916-565decd11f50@I-love.SAKURA.ne.jp> Date: Wed, 16 Nov 2022 18:27:45 +0900 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 6.3; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.4.2 Subject: Re: [syzbot] INFO: task hung in rfkill_global_led_trigger_worker (2) Content-Language: en-US To: Hillf Danton , syzbot , Greg Kroah-Hartman Cc: Peter Zijlstra , Will Deacon , Waiman Long , Boqun Feng , Dmitry Vyukov , linux-kernel@vger.kernel.org, linux-mm@kvack.org, syzkaller-bugs@googlegroups.com References: <20221116041716.2797-1-hdanton@sina.com> From: Tetsuo Handa In-Reply-To: <20221116041716.2797-1-hdanton@sina.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2022/11/16 13:17, Hillf Danton wrote: > No deadlock was reported for syz-executor145/4505 and syz-executor145/4516. > Why? Lockdep should be able to report this real deadlock case. But unfortunately, >> INFO: task syz-executor145:4505 blocked for more than 143 seconds. >> Not tainted 6.1.0-rc5-syzkaller-00008-ge01d50cbd6ee #0 >> "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. >> task:syz-executor145 state:D stack:21896 pid:4505 ppid:3645 flags:0x00004002 >> >> 2 locks held by syz-executor145/4505: >> #0: ffff88807268e100 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:835 [inline] >> #0: ffff88807268e100 (&dev->mutex){....}-{3:3}, at: nfc_unregister_device+0x87/0x290 net/nfc/core.c:1165 >> #1: ffffffff8e787b08 (rfkill_global_mutex){+.+.}-{3:3}, at: rfkill_unregister+0xcb/0x220 net/rfkill/core.c:1130 >> >> INFO: task syz-executor145:4516 blocked for more than 144 seconds. >> Not tainted 6.1.0-rc5-syzkaller-00008-ge01d50cbd6ee #0 >> "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. >> task:syz-executor145 state:D stack:23096 pid:4516 ppid:3647 flags:0x00004004 >> >> 2 locks held by syz-executor145/4516: >> #0: ffffffff8e787b08 (rfkill_global_mutex){+.+.}-{3:3}, at: rfkill_fop_write+0x1b3/0x790 net/rfkill/core.c:1278 >> #1: ffff88807268e100 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:835 [inline] >> #1: ffff88807268e100 (&dev->mutex){....}-{3:3}, at: nfc_dev_down+0x33/0x260 net/nfc/core.c:143 device_initialize() hides dev->mutex from lockdep tests; explained at https://groups.google.com/g/syzkaller-bugs/c/Uj9LqEUCwac/m/BhdTjWhNAQAJ .