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=-7.3 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham 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 46C97C4360C for ; Fri, 27 Sep 2019 05:11:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1735D21783 for ; Fri, 27 Sep 2019 05:11:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1569561061; bh=ls1GkAP3q7Y1jxVP/fVgN6Pw3D11AGVy4cV2gOlLBQ4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=XmKkp5IgqQamC+BtGsXghxiNDwoUt7vKuzhzCaO9wRAaqgpjc22WNYTcsszDpvyW2 O9ikBzkE/ZXFsr/u4g6JHUEbet54L/LxPqccyMTYkNe5oV1mXjBNVV7VaoqmCZBTNa uaW1NicCqZouio2qgUDZHx6Y/YqJAQNyNEf9ebpk= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728356AbfI0FLA (ORCPT ); Fri, 27 Sep 2019 01:11:00 -0400 Received: from mail.kernel.org ([198.145.29.99]:56362 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725268AbfI0FK7 (ORCPT ); Fri, 27 Sep 2019 01:10:59 -0400 Received: from localhost (unknown [62.119.166.9]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 848E22054F; Fri, 27 Sep 2019 05:10:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1569561058; bh=ls1GkAP3q7Y1jxVP/fVgN6Pw3D11AGVy4cV2gOlLBQ4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=JKy4AbNzhC5BVtzJ4z9lhF7ZcnaQJytp/ZFP4CwT7wy3imcfsYP0ANB1H5XBntsgT 5Vh6j6eBzUQ5I3deD1XcTpgOhIHVaQ3XA+f4go0NAyQnjgoS8+PeXiNc+HrMtxDP9S uq8xHaOIbwWfcID7oI/P+mi/EWu5nE2FWot4Xav4= Date: Fri, 27 Sep 2019 07:10:42 +0200 From: Greg Kroah-Hartman To: Alan Stern Cc: Andrey Konovalov , "Rafael J. Wysocki" , syzbot , LKML , USB list , syzkaller-bugs Subject: Re: WARNING in pvr2_i2c_core_done Message-ID: <20190927051042.GA1767219@kroah.com> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.12.2 (2019-09-21) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Sep 26, 2019 at 05:44:31PM -0400, Alan Stern wrote: > On Wed, 25 Sep 2019, Andrey Konovalov wrote: > > > On Wed, Sep 25, 2019 at 4:10 PM Alan Stern wrote: > > > > > > On Wed, 25 Sep 2019, syzbot wrote: > > > > > > > Hello, > > > > > > > > syzbot found the following crash on: > > > > > > > > HEAD commit: d9e63adc usb-fuzzer: main usb gadget fuzzer driver > > > > git tree: https://github.com/google/kasan.git usb-fuzzer > > > > console output: https://syzkaller.appspot.com/x/log.txt?x=16b5fcd5600000 > > > > kernel config: https://syzkaller.appspot.com/x/.config?x=f4fa60e981ee8e6a > > > > dashboard link: https://syzkaller.appspot.com/bug?extid=e74a998ca8f1df9cc332 > > > > compiler: gcc (GCC) 9.0.0 20181231 (experimental) > > > > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=16ec07b1600000 > > > > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=13ff0871600000 > > > > > > > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > > > > Reported-by: syzbot+e74a998ca8f1df9cc332@syzkaller.appspotmail.com > > > > > > > > pvrusb2: Device being rendered inoperable > > > > cx25840 0-0044: Unable to detect h/w, assuming cx23887 > > > > cx25840 0-0044: cx23887 A/V decoder found @ 0x88 (pvrusb2_a) > > > > pvrusb2: Attached sub-driver cx25840 > > > > pvrusb2: ***WARNING*** pvrusb2 device hardware appears to be jammed and I > > > > can't clear it. > > > > pvrusb2: You might need to power cycle the pvrusb2 device in order to > > > > recover. > > > > ------------[ cut here ]------------ > > > > sysfs group 'power' not found for kobject 'i2c-0' > > > > WARNING: CPU: 0 PID: 102 at fs/sysfs/group.c:278 sysfs_remove_group > > > > fs/sysfs/group.c:278 [inline] > > > > WARNING: CPU: 0 PID: 102 at fs/sysfs/group.c:278 > > > > sysfs_remove_group+0x155/0x1b0 fs/sysfs/group.c:269 > > > > > > I have seen a lot of error messages like this one (i.e., "group 'power' > > > not found for kobject"), in runs that involved fuzzing a completely > > > different USB driver. Initial testing failed to find a cause. > > > > > > This leads me to wonder whether the problem might lie somewhere else > > > entirely. A bug in some core kernel code? Memory corruption? > > > > AFAICS so far this has only been triggered from the usbvision driver > > [1] and from the pvrusb2 driver (this report). > > > > I wanted to loop in sysfs maintainers, but it seems that Greg and > > Rafael are already cc'ed on this. > > > > [1] https://syzkaller.appspot.com/bug?extid=7fa38a608b1075dfd634 > > It turns out the reason for this error is simple: The driver > unregisters its subdevices in the release handler instead of in the > disconnect handler. There probably is documentation about this > somewhere, but I don't know exactly where -- maybe Greg remembers. Nope, I don't remember. It should happen in the disconnect handler, odd of it to be in release, but maybe that's the "easiest" way for v4l to handle this? thanks, greg k-h