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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,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 91BFEC433E0 for ; Mon, 25 May 2020 13:33:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6DD7C2084C for ; Mon, 25 May 2020 13:33:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390745AbgEYNdG (ORCPT ); Mon, 25 May 2020 09:33:06 -0400 Received: from www262.sakura.ne.jp ([202.181.97.72]:61288 "EHLO www262.sakura.ne.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388794AbgEYNdF (ORCPT ); Mon, 25 May 2020 09:33:05 -0400 Received: from fsav301.sakura.ne.jp (fsav301.sakura.ne.jp [153.120.85.132]) by www262.sakura.ne.jp (8.15.2/8.15.2) with ESMTP id 04PDWgrl096514; Mon, 25 May 2020 22:32:42 +0900 (JST) (envelope-from penguin-kernel@i-love.sakura.ne.jp) Received: from www262.sakura.ne.jp (202.181.97.72) by fsav301.sakura.ne.jp (F-Secure/fsigk_smtp/550/fsav301.sakura.ne.jp); Mon, 25 May 2020 22:32:42 +0900 (JST) X-Virus-Status: clean(F-Secure/fsigk_smtp/550/fsav301.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 04PDWgn4096507 (version=TLSv1.2 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Mon, 25 May 2020 22:32:42 +0900 (JST) (envelope-from penguin-kernel@i-love.sakura.ne.jp) Subject: Re: [PATCH] USB: cdc-wdm: Call wake_up_all() when clearing WDM_IN_USE bit. To: Oliver Neukum Cc: Greg KH , Colin Ian King , Arnd Bergmann , linux-usb@vger.kernel.org References: <20200520233129.3704-1-penguin-kernel@I-love.SAKURA.ne.jp> <20200521073323.GA2579717@kroah.com> <177cc23a-60a7-f5cd-09d6-57608727ea27@i-love.sakura.ne.jp> <1590090636.6470.12.camel@suse.com> <1590134662.19681.12.camel@suse.com> <03894591-a1ac-496a-a35f-55953e5bcc06@i-love.sakura.ne.jp> <1590408381.2838.4.camel@suse.com> From: Tetsuo Handa Message-ID: <4a686d9a-d09f-44f3-553c-bcf0bd8a8ea1@i-love.sakura.ne.jp> Date: Mon, 25 May 2020 22:32:38 +0900 User-Agent: Mozilla/5.0 (Windows NT 6.3; Win64; x64; rv:68.0) Gecko/20100101 Thunderbird/68.8.1 MIME-Version: 1.0 In-Reply-To: <1590408381.2838.4.camel@suse.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-usb-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org On 2020/05/25 21:06, Oliver Neukum wrote: > Am Freitag, den 22.05.2020, 17:26 +0900 schrieb Tetsuo Handa: >> On 2020/05/22 17:04, Oliver Neukum wrote: >>> May I ask you to redo the patch with comments added stating >>> that the wake up is done for the sake of wdm_flush(), change >>> the description and add the link to syzkaller? >> >> You can take over this patch. syzbot tried this patch on 2020/02/11 01:23 at >> https://syzkaller.appspot.com/bug?id=e7b761593b23eb50855b9ea31e3be5472b711186 , >> but this patch did not solve the problem syzbot has found. Thus, I don't add >> a link to syzkaller... > > Hi, > > this is odd. I looked at the driver and it looks to me like > pre/post_reset() is the only other place that touches WDM_IN_USE. > And it does so correctly. Any idea what could be wrong? I haven't understood the root cause of this problem. You were in the thread at https://groups.google.com/forum/#!msg/syzkaller-bugs/q3QMjt_t83c/GqP58GaTAQAJ . My patch was made from that thread (which simply makes sure to call wake_up_all() when clearing WDM_IN_USE bit) apart from the root cause of this problem.