From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pl0-f69.google.com (mail-pl0-f69.google.com [209.85.160.69]) by kanga.kvack.org (Postfix) with ESMTP id DFB086B06F5 for ; Sat, 12 May 2018 17:50:49 -0400 (EDT) Received: by mail-pl0-f69.google.com with SMTP id d9-v6so7444799plj.4 for ; Sat, 12 May 2018 14:50:49 -0700 (PDT) Received: from mail-sor-f65.google.com (mail-sor-f65.google.com. [209.85.220.65]) by mx.google.com with SMTPS id b185-v6sor2372986pgc.146.2018.05.12.14.50.17 for (Google Transport Security); Sat, 12 May 2018 14:50:17 -0700 (PDT) Date: Sat, 12 May 2018 14:52:22 -0700 From: Eric Biggers Subject: Re: BUG: workqueue lockup (2) Message-ID: <20180512215222.GC817@sol.localdomain> References: <94eb2c03c9bc75aff2055f70734c@google.com> <001a113f711a528a3f0560b08e76@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <001a113f711a528a3f0560b08e76@google.com> Sender: owner-linux-mm@kvack.org List-ID: To: syzbot Cc: dvyukov@google.com, gregkh@linuxfoundation.org, kstewart@linuxfoundation.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, penguin-kernel@I-love.SAKURA.ne.jp, pombredanne@nexb.com, syzkaller-bugs@googlegroups.com, tglx@linutronix.de On Tue, Dec 19, 2017 at 04:25:01AM -0800, syzbot wrote: > syzkaller has found reproducer for the following crash on > f3b5ad89de16f5d42e8ad36fbdf85f705c1ae051 > git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/master > compiler: gcc (GCC) 7.1.1 20170620 > .config is attached > Raw console output is attached. > C reproducer is attached > syzkaller reproducer is attached. See https://goo.gl/kgGztJ > for information about syzkaller reproducers > > > BUG: workqueue lockup - pool cpus=1 node=0 flags=0x0 nice=0 stuck for 37s! > BUG: workqueue lockup - pool cpus=1 node=0 flags=0x0 nice=-20 stuck for 32s! > Showing busy workqueues and worker pools: > workqueue events: flags=0x0 > pwq 2: cpus=1 node=0 flags=0x0 nice=0 active=1/256 > pending: cache_reap > workqueue events_power_efficient: flags=0x80 > pwq 2: cpus=1 node=0 flags=0x0 nice=0 active=2/256 > pending: neigh_periodic_work, do_cache_clean > workqueue mm_percpu_wq: flags=0x8 > pwq 2: cpus=1 node=0 flags=0x0 nice=0 active=1/256 > pending: vmstat_update > workqueue kblockd: flags=0x18 > pwq 3: cpus=1 node=0 flags=0x0 nice=-20 active=1/256 > pending: blk_timeout_work > The bug that this reproducer reproduces was fixed a while ago by commit 966031f340185e, so I'm marking this bug report fixed by it: #syz fix: n_tty: fix EXTPROC vs ICANON interaction with TIOCINQ (aka FIONREAD) Note that the error message was not always "BUG: workqueue lockup"; it was also sometimes like "watchdog: BUG: soft lockup - CPU#5 stuck for 22s!". syzbot still is hitting the "BUG: workqueue lockup" error sometimes, but it must be for other reasons. None has a reproducer currently. - Eric