From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from tartarus.angband.pl ([89.206.35.136]:33920 "EHLO tartarus.angband.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750769AbeAFFLI (ORCPT ); Sat, 6 Jan 2018 00:11:08 -0500 Received: from kilobyte by tartarus.angband.pl with local (Exim 4.89) (envelope-from ) id 1eXgl1-0008Mj-MV for linux-btrfs@vger.kernel.org; Sat, 06 Jan 2018 06:10:59 +0100 Date: Sat, 6 Jan 2018 06:10:59 +0100 From: Adam Borowski To: linux-btrfs@vger.kernel.org Subject: hang in btrfs_async_reclaim_metadata_space Message-ID: <20180106051059.kpultyyfhgxjowf5@angband.pl> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-btrfs-owner@vger.kernel.org List-ID: Hi! I got a reproducible infinite hang, reliably triggered by the testsuite of "flatpak"; fails on at least 4.15-rc6, 4.9.75, and on another machine with Debian's 4.14.2-1. [580632.355107] INFO: task kworker/u8:2:11105 blocked for more than 120 seconds. [580632.355120] Not tainted 4.14.0-1-amd64 #1 Debian 4.14.2-1 [580632.355124] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [580632.355129] kworker/u8:2 D 0 11105 2 0x80000000 [580632.355176] Workqueue: events_unbound btrfs_async_reclaim_metadata_space [btrfs] [580632.355179] Call Trace: [580632.355192] __schedule+0x28e/0x880 [580632.355196] schedule+0x2c/0x80 [580632.355200] wb_wait_for_completion+0x64/0x90 [580632.355205] ? finish_wait+0x80/0x80 [580632.355207] __writeback_inodes_sb_nr+0xa1/0xd0 [580632.355210] writeback_inodes_sb_nr+0x10/0x20 [580632.355235] flush_space+0x3ed/0x520 [btrfs] [580632.355238] ? pick_next_task_fair+0x158/0x590 [580632.355242] ? __switch_to+0x1f3/0x460 [580632.355267] btrfs_async_reclaim_metadata_space+0xf6/0x4a0 [btrfs] [580632.355278] process_one_work+0x198/0x390 [580632.355281] worker_thread+0x35/0x3c0 [580632.355284] kthread+0x125/0x140 [580632.355287] ? process_one_work+0x390/0x390 [580632.355289] ? kthread_create_on_node+0x70/0x70 [580632.355292] ? SyS_exit_group+0x14/0x20 [580632.355295] ret_from_fork+0x25/0x30 The machines are distinct enough that this probably should happen everywhere: AMD Phenom2, SSD, noatime,compress=lzo,space_cache=v2 Intel Braswell, rust, noatime,autodefrag,space_cache=v2 Meow! -- // If you believe in so-called "intellectual property", please immediately // cease using counterfeit alphabets. Instead, contact the nearest temple // of Amon, whose priests will provide you with scribal services for all // your writing needs, for Reasonable And Non-Discriminatory prices.