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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 94747C433FF for ; Tue, 13 Aug 2019 07:35:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 66B8420679 for ; Tue, 13 Aug 2019 07:35:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727533AbfHMHf4 (ORCPT ); Tue, 13 Aug 2019 03:35:56 -0400 Received: from gofer.mess.org ([88.97.38.141]:50005 "EHLO gofer.mess.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725820AbfHMHf4 (ORCPT ); Tue, 13 Aug 2019 03:35:56 -0400 Received: by gofer.mess.org (Postfix, from userid 1000) id CD874603E8; Tue, 13 Aug 2019 08:35:52 +0100 (BST) Date: Tue, 13 Aug 2019 08:35:52 +0100 From: Sean Young To: Ezequiel Garcia Cc: syzbot , andreyknvl@google.com, linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, linux-usb@vger.kernel.org, mchehab@kernel.org, syzkaller-bugs@googlegroups.com Subject: Re: [PATCH] media: em28xx: modules workqueue not inited for 2nd device Message-ID: <20190813073552.ygvwvjibhha5k76b@gofer.mess.org> References: <0000000000004bcc0d058faf01c4@google.com> <20190811051110.hsdwmjrbvqgrmssc@gofer.mess.org> <614221186ed37383778d8890d39e829a0e924796.camel@collabora.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <614221186ed37383778d8890d39e829a0e924796.camel@collabora.com> User-Agent: NeoMutt/20170113 (1.7.2) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Aug 12, 2019 at 10:21:39AM -0300, Ezequiel Garcia wrote: > On Sun, 2019-08-11 at 06:11 +0100, Sean Young wrote: > > syzbot reports an error on flush_request_modules() for the second device. > > This workqueue was never initialised so simply remove the offending line. > > > > usb 1-1: USB disconnect, device number 2 > > em28xx 1-1:1.153: Disconnecting em28xx #1 > > ------------[ cut here ]------------ > > WARNING: CPU: 0 PID: 12 at kernel/workqueue.c:3031 > > __flush_work.cold+0x2c/0x36 kernel/workqueue.c:3031 > > Kernel panic - not syncing: panic_on_warn set ... > > CPU: 0 PID: 12 Comm: kworker/0:1 Not tainted 5.3.0-rc2+ #25 > > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS > > Google 01/01/2011 > > Workqueue: usb_hub_wq hub_event > > Call Trace: > > __dump_stack lib/dump_stack.c:77 [inline] > > dump_stack+0xca/0x13e lib/dump_stack.c:113 > > panic+0x2a3/0x6da kernel/panic.c:219 > > __warn.cold+0x20/0x4a kernel/panic.c:576 > > report_bug+0x262/0x2a0 lib/bug.c:186 > > fixup_bug arch/x86/kernel/traps.c:179 [inline] > > fixup_bug arch/x86/kernel/traps.c:174 [inline] > > do_error_trap+0x12b/0x1e0 arch/x86/kernel/traps.c:272 > > do_invalid_op+0x32/0x40 arch/x86/kernel/traps.c:291 > > invalid_op+0x23/0x30 arch/x86/entry/entry_64.S:1026 > > RIP: 0010:__flush_work.cold+0x2c/0x36 kernel/workqueue.c:3031 > > Code: 9a 22 00 48 c7 c7 20 e4 c5 85 e8 d9 3a 0d 00 0f 0b 45 31 e4 e9 98 86 > > ff ff e8 51 9a 22 00 48 c7 c7 20 e4 c5 85 e8 be 3a 0d 00 <0f> 0b 45 31 e4 > > e9 7d 86 ff ff e8 36 9a 22 00 48 c7 c7 20 e4 c5 85 > > RSP: 0018:ffff8881da20f720 EFLAGS: 00010286 > > RAX: 0000000000000024 RBX: dffffc0000000000 RCX: 0000000000000000 > > RDX: 0000000000000000 RSI: ffffffff8128a0fd RDI: ffffed103b441ed6 > > RBP: ffff8881da20f888 R08: 0000000000000024 R09: fffffbfff11acd9a > > R10: fffffbfff11acd99 R11: ffffffff88d66ccf R12: 0000000000000000 > > R13: 0000000000000001 R14: ffff8881c6685df8 R15: ffff8881d2a85b78 > > flush_request_modules drivers/media/usb/em28xx/em28xx-cards.c:3325 [inline] > > em28xx_usb_disconnect.cold+0x280/0x2a6 > > drivers/media/usb/em28xx/em28xx-cards.c:4023 > > usb_unbind_interface+0x1bd/0x8a0 drivers/usb/core/driver.c:423 > > __device_release_driver drivers/base/dd.c:1120 [inline] > > device_release_driver_internal+0x404/0x4c0 drivers/base/dd.c:1151 > > bus_remove_device+0x2dc/0x4a0 drivers/base/bus.c:556 > > device_del+0x420/0xb10 drivers/base/core.c:2288 > > usb_disable_device+0x211/0x690 drivers/usb/core/message.c:1237 > > usb_disconnect+0x284/0x8d0 drivers/usb/core/hub.c:2199 > > hub_port_connect drivers/usb/core/hub.c:4949 [inline] > > hub_port_connect_change drivers/usb/core/hub.c:5213 [inline] > > port_event drivers/usb/core/hub.c:5359 [inline] > > hub_event+0x1454/0x3640 drivers/usb/core/hub.c:5441 > > process_one_work+0x92b/0x1530 kernel/workqueue.c:2269 > > process_scheduled_works kernel/workqueue.c:2331 [inline] > > worker_thread+0x7ab/0xe20 kernel/workqueue.c:2417 > > kthread+0x318/0x420 kernel/kthread.c:255 > > ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 > > Kernel Offset: disabled > > Rebooting in 86400 seconds.. > > > > Reported-by: syzbot+b7f57261c521087d89bb@syzkaller.appspotmail.com > > Signed-off-by: Sean Young > > I reviewed the syzbot report, but was left head-scratching and > failing to see how the module-loading worker was supposed to be used :-) > > Reviewed-by: Ezequiel Garcia > > Also, this seems a bug, so how about this tag? > > Fixes: be7fd3c3a8c5e ("media: em28xx: Hauppauge DualHD second tuner functionality) Thank you for the review and yes it does need that tag. Thanks sean > > > --- > > drivers/media/usb/em28xx/em28xx-cards.c | 1 - > > 1 file changed, 1 deletion(-) > > > > diff --git a/drivers/media/usb/em28xx/em28xx-cards.c b/drivers/media/usb/em28xx/em28xx-cards.c > > index 6e33782c3ca6..5983e72a0622 100644 > > --- a/drivers/media/usb/em28xx/em28xx-cards.c > > +++ b/drivers/media/usb/em28xx/em28xx-cards.c > > @@ -4019,7 +4019,6 @@ static void em28xx_usb_disconnect(struct usb_interface *intf) > > dev->dev_next->disconnected = 1; > > dev_info(&dev->intf->dev, "Disconnecting %s\n", > > dev->dev_next->name); > > - flush_request_modules(dev->dev_next); > > } > > > > dev->disconnected = 1; >