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=-13.4 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_IN_DEF_DKIM_WL 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 74A02C433DF for ; Thu, 21 May 2020 16:27:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3C8A420759 for ; Thu, 21 May 2020 16:27:45 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="K0o/kvZd" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729825AbgEUQ1o (ORCPT ); Thu, 21 May 2020 12:27:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45250 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728456AbgEUQ1o (ORCPT ); Thu, 21 May 2020 12:27:44 -0400 Received: from mail-pf1-x441.google.com (mail-pf1-x441.google.com [IPv6:2607:f8b0:4864:20::441]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 00188C061A0E for ; Thu, 21 May 2020 09:27:43 -0700 (PDT) Received: by mail-pf1-x441.google.com with SMTP id v63so3547703pfb.10 for ; Thu, 21 May 2020 09:27:43 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=XPwZ+enoWr5eA6loAPCV/3vkjRfgUo7mHTVFxuPxPJA=; b=K0o/kvZd1FrauoOoPLW79wpOUfthDpAtsz4c6wZg78XJGe/LVr9n6l0l4+3kGHKKvt bz0dAkAkWKheWE+2A4xBK9KiowmXAICD0XVom1/cceOVp701ktoEiUm3pvDMHPdP0F64 U8xDrI46PxNQOHAHgvtymtMiC269LwH/2d6Yi0AG+g+fjeqr6iVC2fUCYPLdVdIPGBGe e43QjPKt5EXcE3nZ09hLE3wVKOpsYNv73Qj3kYZEfpBE0oqJ8XcftNHlmmb38msOVOpj AlgPb0yHf7fBA1+Gr6gkbSNU5g/bcJCaZ+nEG779S/TogJefDSPp7orTajn4GEXHjusd 3MFA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=XPwZ+enoWr5eA6loAPCV/3vkjRfgUo7mHTVFxuPxPJA=; b=mAhdpkjlAfh1SeaAbJ8Ly0CeECxAQX+OF0YUu/D8D2TOQtTLwFLmWgbSLMWNkorPuZ SjreQ3tJ603Tdg9tcSUBKIw8QQbw/EoPDYH6wrgb5F/frdDMBwCXW61hoveehIxtU3Ng SO2YgmfBx11HT8yNPowjnjCzNHv/x9iQBN+wXCwQto+CindZfJN1TkJGkUI8hdE0XuvP xfHGee28c38uZaa/ZErS46uRdvyj6uILTmRPGLzLGK8I3q6xCJaAlqv7qjbDwxo6d+bJ n26YljKSVl8CgDFsb5gGJY8qNOYACLNxp+aNLwW74Zm7WV9LBSFGDx+YL2qGt9hcRItd SVYw== X-Gm-Message-State: AOAM5324u5EAdi6c6xiWtj+vngtj8HnBArPfHGtEquOK0oQBL1AGIvX1 zJT4NUI+l05YIE/wjELD9j1cWc4E7GDDKooZRrjPDg== X-Google-Smtp-Source: ABdhPJyhrDZVw0Nbp8P1qW7tdXCZlOqTFixwpervkVjXRYTXOhPi4XGyUBCTzZZ5nBM7CYT19usk2wiZJTKdNjs5FFE= X-Received: by 2002:a62:8647:: with SMTP id x68mr10127197pfd.178.1590078463184; Thu, 21 May 2020 09:27:43 -0700 (PDT) MIME-Version: 1.0 References: <000000000000c866c705a61a95d4@google.com> <9a337dfa-175f-e13b-1977-0f63d589f37c@I-love.SAKURA.ne.jp> <0bc8334572c0716e8dcad2ec3b623f20cefdfde3.camel@kernel.org> In-Reply-To: <0bc8334572c0716e8dcad2ec3b623f20cefdfde3.camel@kernel.org> From: Andrey Konovalov Date: Thu, 21 May 2020 18:27:32 +0200 Message-ID: Subject: Re: INFO: task hung in locks_remove_posix To: Jeff Layton , Tetsuo Handa Cc: syzbot , syzkaller-bugs , LKML Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, May 21, 2020 at 4:48 PM Jeff Layton wrote: > > On Thu, 2020-05-21 at 23:09 +0900, Tetsuo Handa wrote: > > On 2020/05/21 5:53, syzbot wrote: > > > Hello, > > > > > > syzbot found the following crash on: > > > > > > HEAD commit: 806d8acc USB: dummy-hcd: use configurable endpoint naming .. > > > git tree: https://github.com/google/kasan.git usb-fuzzer > > > console output: https://syzkaller.appspot.com/x/log.txt?x=16c9ece2100000 > > > kernel config: https://syzkaller.appspot.com/x/.config?x=d800e9bad158025f > > > dashboard link: https://syzkaller.appspot.com/bug?extid=f5bc30abd8916982419c > > > compiler: gcc (GCC) 9.0.0 20181231 (experimental) > > > > > > Unfortunately, I don't have any reproducer for this crash yet. > > > > This seems to be a mislabeling due to '?' in all lines in a trace. > > > > #syz dup: INFO: task hung in wdm_flush > > > I'm not sure I trust those stack traces. The console output shows '?' > characters in front of every frame. Doesn't that mean that that address > it found on the stack is unreliable? > > In principle, unless you're overriding the filp->lock operation (and the > wdm fs doesn't do that, afaict), locks_remove_posix should not block. > I'll also note that there is some of this in the logs before the hung > task warnings: > > [ 182.020388][ T12] usb 5-1: too many endpoints for config 0 interface 107 altsetting 116: 116, using maximum allowed: 30 > [ 182.031661][ T12] usb 5-1: config 0 interface 107 altsetting 116 has 0 endpoint descriptors, different from the interface descriptor's value: 116 > [ 182.045145][ T12] usb 5-1: config 0 interface 107 has no altsetting 0 > [ 182.052028][ T12] usb 5-1: New USB device found, idVendor=0926, idProduct=3333, bcdDevice= 0.40 > [ 182.060120][ T3525] usb 6-1: USB disconnect, device number 20 > [ 182.061148][ C0] xpad 6-1:0.65: xpad_irq_out - usb_submit_urb failed with result -19 > [ 182.075465][ T3525] xpad 6-1:0.65: xpad_try_sending_next_out_packet - usb_submit_urb failed with result -19 > [ 182.075565][ T12] usb 5-1: New USB device strings: Mfr=0, Product=0, SerialNumber=0 > [ 182.109020][ T12] usb 5-1: config 0 descriptor?? > [ 182.136857][ T163] usb usb2-port1: attempt power cycle > [ 182.410396][ T4447] udc-core: couldn't find an available UDC or it's busy > [ 182.417562][ T4447] misc raw-gadget: fail, usb_gadget_probe_driver returned -16 > [ 182.856513][ T163] usb 2-1: new high-speed USB device number 18 using dummy_hcd > [ 183.026601][ T163] usb 2-1: device descriptor read/8, error -61 > [ 183.236577][ T163] usb 2-1: device descriptor read/8, error -71 > [ 184.068991][ T3525] usb 5-1: USB disconnect, device number 21 > [ 206.185571][ T23] INFO: task syz-executor.2:3145 blocked for more than 143 seconds. > [ 206.193630][ T23] Not tainted 5.7.0-rc5-syzkaller #0 > [ 206.199512][ T23] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. > [ 206.208242][ T23] syz-executor.2 D28552 3145 370 0x80004006 > > ...which leads me to believe that this might have more to do with the > USB subsystem than anything in the posix locking code. > > In any case, I doubt there's much we can do here without a more reliable > stack trace to work from. That call stack doesn't seem to make much > sense. Most likely this is a duplicate of: https://syzkaller.appspot.com/bug?id=e7b761593b23eb50855b9ea31e3be5472b711186 (with more than 30000 crashes now :) #syz dup: INFO: task hung in wdm_flush