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=-6.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_PASS,URIBL_BLOCKED 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 E0B01C10F0E for ; Mon, 15 Apr 2019 18:40:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AD28E218A1 for ; Mon, 15 Apr 2019 18:40:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728059AbfDOSkB (ORCPT ); Mon, 15 Apr 2019 14:40:01 -0400 Received: from gateway21.websitewelcome.com ([192.185.45.212]:42543 "EHLO gateway21.websitewelcome.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727845AbfDOSkA (ORCPT ); Mon, 15 Apr 2019 14:40:00 -0400 Received: from cm14.websitewelcome.com (cm14.websitewelcome.com [100.42.49.7]) by gateway21.websitewelcome.com (Postfix) with ESMTP id 22893400C6EA9 for ; Mon, 15 Apr 2019 13:39:59 -0500 (CDT) Received: from gator4166.hostgator.com ([108.167.133.22]) by cmsmtp with SMTP id G6WNheaZK2qH7G6WNh0ela; Mon, 15 Apr 2019 13:39:59 -0500 X-Authority-Reason: nr=8 Received: from [189.250.55.242] (port=49958 helo=[192.168.43.131]) by gator4166.hostgator.com with esmtpsa (TLSv1.2:ECDHE-RSA-AES128-GCM-SHA256:128) (Exim 4.91) (envelope-from ) id 1hG6WM-003xlY-LG; Mon, 15 Apr 2019 13:39:58 -0500 Subject: Re: INFO: task hung in usb_kill_urb To: Andrey Konovalov , Alan Stern Cc: Greg Kroah-Hartman , Kernel development list , USB list , syzkaller-bugs References: <0000000000006f1596058653d991@google.com> From: "Gustavo A. R. Silva" Openpgp: preference=signencrypt Autocrypt: addr=gustavo@embeddedor.com; keydata= mQINBFssHAwBEADIy3ZoPq3z5UpsUknd2v+IQud4TMJnJLTeXgTf4biSDSrXn73JQgsISBwG 2Pm4wnOyEgYUyJd5tRWcIbsURAgei918mck3tugT7AQiTUN3/5aAzqe/4ApDUC+uWNkpNnSV tjOx1hBpla0ifywy4bvFobwSh5/I3qohxDx+c1obd8Bp/B/iaOtnq0inli/8rlvKO9hp6Z4e DXL3PlD0QsLSc27AkwzLEc/D3ZaqBq7ItvT9Pyg0z3Q+2dtLF00f9+663HVC2EUgP25J3xDd 496SIeYDTkEgbJ7WYR0HYm9uirSET3lDqOVh1xPqoy+U9zTtuA9NQHVGk+hPcoazSqEtLGBk YE2mm2wzX5q2uoyptseSNceJ+HE9L+z1KlWW63HhddgtRGhbP8pj42bKaUSrrfDUsicfeJf6 m1iJRu0SXYVlMruGUB1PvZQ3O7TsVfAGCv85pFipdgk8KQnlRFkYhUjLft0u7CL1rDGZWDDr NaNj54q2CX9zuSxBn9XDXvGKyzKEZ4NY1Jfw+TAMPCp4buawuOsjONi2X0DfivFY+ZsjAIcx qQMglPtKk/wBs7q2lvJ+pHpgvLhLZyGqzAvKM1sVtRJ5j+ARKA0w4pYs5a5ufqcfT7dN6TBk LXZeD9xlVic93Ju08JSUx2ozlcfxq+BVNyA+dtv7elXUZ2DrYwARAQABtCxHdXN0YXZvIEEu IFIuIFNpbHZhIDxndXN0YXZvQGVtYmVkZGVkb3IuY29tPokCPQQTAQgAJwUCWywcDAIbIwUJ CWYBgAULCQgHAgYVCAkKCwIEFgIDAQIeAQIXgAAKCRBHBbTLRwbbMZ6tEACk0hmmZ2FWL1Xi l/bPqDGFhzzexrdkXSfTTZjBV3a+4hIOe+jl6Rci/CvRicNW4H9yJHKBrqwwWm9fvKqOBAg9 obq753jydVmLwlXO7xjcfyfcMWyx9QdYLERTeQfDAfRqxir3xMeOiZwgQ6dzX3JjOXs6jHBP cgry90aWbaMpQRRhaAKeAS14EEe9TSIly5JepaHoVdASuxklvOC0VB0OwNblVSR2S5i5hSsh ewbOJtwSlonsYEj4EW1noQNSxnN/vKuvUNegMe+LTtnbbocFQ7dGMsT3kbYNIyIsp42B5eCu JXnyKLih7rSGBtPgJ540CjoPBkw2mCfhj2p5fElRJn1tcX2McsjzLFY5jK9RYFDavez5w3lx JFgFkla6sQHcrxH62gTkb9sUtNfXKucAfjjCMJ0iuQIHRbMYCa9v2YEymc0k0RvYr43GkA3N PJYd/vf9vU7VtZXaY4a/dz1d9dwIpyQARFQpSyvt++R74S78eY/+lX8wEznQdmRQ27kq7BJS R20KI/8knhUNUJR3epJu2YFT/JwHbRYC4BoIqWl+uNvDf+lUlI/D1wP+lCBSGr2LTkQRoU8U 64iK28BmjJh2K3WHmInC1hbUucWT7Swz/+6+FCuHzap/cjuzRN04Z3Fdj084oeUNpP6+b9yW e5YnLxF8ctRAp7K4yVlvA7kCDQRbLBwMARAAsHCE31Ffrm6uig1BQplxMV8WnRBiZqbbsVJB H1AAh8tq2ULl7udfQo1bsPLGGQboJSVN9rckQQNahvHAIK8ZGfU4Qj8+CER+fYPp/MDZj+t0 DbnWSOrG7z9HIZo6PR9z4JZza3Hn/35jFggaqBtuydHwwBANZ7A6DVY+W0COEU4of7CAahQo 5NwYiwS0lGisLTqks5R0Vh+QpvDVfuaF6I8LUgQR/cSgLkR//V1uCEQYzhsoiJ3zc1HSRyOP otJTApqGBq80X0aCVj1LOiOF4rrdvQnj6iIlXQssdb+WhSYHeuJj1wD0ZlC7ds5zovXh+FfF l5qH5RFY/qVn3mNIVxeO987WSF0jh+T5ZlvUNdhedGndRmwFTxq2Li6GNMaolgnpO/CPcFpD jKxY/HBUSmaE9rNdAa1fCd4RsKLlhXda+IWpJZMHlmIKY8dlUybP+2qDzP2lY7kdFgPZRU+e zS/pzC/YTzAvCWM3tDgwoSl17vnZCr8wn2/1rKkcLvTDgiJLPCevqpTb6KFtZosQ02EGMuHQ I6Zk91jbx96nrdsSdBLGH3hbvLvjZm3C+fNlVb9uvWbdznObqcJxSH3SGOZ7kCHuVmXUcqoz ol6ioMHMb+InrHPP16aVDTBTPEGwgxXI38f7SUEn+NpbizWdLNz2hc907DvoPm6HEGCanpcA EQEAAYkCJQQYAQgADwUCWywcDAIbDAUJCWYBgAAKCRBHBbTLRwbbMdsZEACUjmsJx2CAY+QS UMebQRFjKavwXB/xE7fTt2ahuhHT8qQ/lWuRQedg4baInw9nhoPE+VenOzhGeGlsJ0Ys52sd XvUjUocKgUQq6ekOHbcw919nO5L9J2ejMf/VC/quN3r3xijgRtmuuwZjmmi8ct24TpGeoBK4 WrZGh/1hAYw4ieARvKvgjXRstcEqM5thUNkOOIheud/VpY+48QcccPKbngy//zNJWKbRbeVn imua0OpqRXhCrEVm/xomeOvl1WK1BVO7z8DjSdEBGzbV76sPDJb/fw+y+VWrkEiddD/9CSfg fBNOb1p1jVnT2mFgGneIWbU0zdDGhleI9UoQTr0e0b/7TU+Jo6TqwosP9nbk5hXw6uR5k5PF 8ieyHVq3qatJ9K1jPkBr8YWtI5uNwJJjTKIA1jHlj8McROroxMdI6qZ/wZ1ImuylpJuJwCDC ORYf5kW61fcrHEDlIvGc371OOvw6ejF8ksX5+L2zwh43l/pKkSVGFpxtMV6d6J3eqwTafL86 YJWH93PN+ZUh6i6Rd2U/i8jH5WvzR57UeWxE4P8bQc0hNGrUsHQH6bpHV2lbuhDdqo+cM9eh GZEO3+gCDFmKrjspZjkJbB5Gadzvts5fcWGOXEvuT8uQSvl+vEL0g6vczsyPBtqoBLa9SNrS VtSixD1uOgytAP7RWS474w== Message-ID: <52ac871b-ac61-432e-3a85-47b8e97233d2@embeddedor.com> Date: Mon, 15 Apr 2019 13:39:57 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - gator4166.hostgator.com X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - embeddedor.com X-BWhitelist: no X-Source-IP: 189.250.55.242 X-Source-L: No X-Exim-ID: 1hG6WM-003xlY-LG X-Source: X-Source-Args: X-Source-Dir: X-Source-Sender: ([192.168.43.131]) [189.250.55.242]:49958 X-Source-Auth: gustavo@embeddedor.com X-Email-Count: 4 X-Source-Cap: Z3V6aWRpbmU7Z3V6aWRpbmU7Z2F0b3I0MTY2Lmhvc3RnYXRvci5jb20= X-Local-Domain: yes Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 4/15/19 12:48 PM, Andrey Konovalov wrote: > On Fri, Apr 12, 2019 at 9:46 PM Alan Stern wrote: >> >> Andrey: >> >> It's really hard to tell just what's going on here. >> >> On Fri, 12 Apr 2019, syzbot wrote: >> >>> Hello, >>> >>> syzbot found the following crash on: >>> >>> HEAD commit: 9a33b369 usb-fuzzer: main usb gadget fuzzer driver >>> git tree: https://github.com/google/kasan/tree/usb-fuzzer >>> console output: https://syzkaller.appspot.com/x/log.txt?x=14c4c1af200000 >>> kernel config: https://syzkaller.appspot.com/x/.config?x=23e37f59d94ddd15 >>> dashboard link: https://syzkaller.appspot.com/bug?extid=d919b0f29d7b5a4994b9 >>> compiler: gcc (GCC) 9.0.0 20181231 (experimental) >>> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=14410dbb200000 >>> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12f0acd3200000 >>> >>> IMPORTANT: if you fix the bug, please add the following tag to the commit: >>> Reported-by: syzbot+d919b0f29d7b5a4994b9@syzkaller.appspotmail.com >>> >>> usb-fuzzer-gadget dummy_udc.0: failed to start USB fuzzer: -22 >>> usb-fuzzer-gadget dummy_udc.0: failed to start USB fuzzer: -22 >>> usb-fuzzer-gadget dummy_udc.0: failed to start USB fuzzer: -22 >>> usb-fuzzer-gadget dummy_udc.0: failed to start USB fuzzer: -22 >>> usb-fuzzer-gadget dummy_udc.0: failed to start USB fuzzer: -22 >>> INFO: task kworker/0:2:532 blocked for more than 143 seconds. >>> Not tainted 5.1.0-rc4-319354-g9a33b36 #3 >>> "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. >>> kworker/0:2 D26656 532 2 0x80000000 >>> Workqueue: usb_hub_wq hub_event >>> Call Trace: >>> schedule+0x8f/0x180 kernel/sched/core.c:3562 >>> usb_kill_urb drivers/usb/core/urb.c:695 [inline] >>> usb_kill_urb+0x22a/0x2c0 drivers/usb/core/urb.c:687 >>> usb_start_wait_urb+0x257/0x4d0 drivers/usb/core/message.c:63 >>> usb_internal_control_msg drivers/usb/core/message.c:101 [inline] >>> usb_control_msg+0x321/0x4a0 drivers/usb/core/message.c:152 >> >> It looks like something is stuck waiting for usb_kill_urb() to finish. >> But what happened before that? > > This crash is somewhat special. It happens quite often during USB > fuzzing, but at the same time it's a hang, which makes it a bit harder > debug. I initially thought that is somehow related to my custom USB > fuzzing kernel patches, but then I saw that someone else hit this > issue while doing USB fuzzing in a completely different way that > doesn't require kernel modifications. So it might be an actual issue > in the kernel. > > The full console output is provided by the syzbot, but I guess it's > not very useful in this case. I've just made sure that this issue is > manually reproducible, so we can easily retest it with debug patches > (syzbot should be also able to do that via the syz test command). Or > is there a way to turn on some verbose mode to see some USB debug > messages? > >> >> I can't tell from the reproducer source, because it uses a bunch of >> special stuff you added in your usb-fuzzer tree. >> >> Alan Stern >> > > I understand, for now I guess the simpler way to debug this is to run > the reproducer. I'll write you and Greg a separate email regarding all > that special stuff that I added. > Hi Andrey, Please, CC me on that email too. Thanks -- Gustavo