From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f41.google.com ([74.125.82.41]:33429 "EHLO mail-wm0-f41.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754662AbcBPKbX (ORCPT ); Tue, 16 Feb 2016 05:31:23 -0500 Received: by mail-wm0-f41.google.com with SMTP id g62so184627869wme.0 for ; Tue, 16 Feb 2016 02:31:22 -0800 (PST) Received: from [10.3.28.25] ([155.210.217.96]) by smtp.gmail.com with ESMTPSA id x186sm19843865wmg.19.2016.02.16.02.31.20 for (version=TLSv1/SSLv3 cipher=OTHER); Tue, 16 Feb 2016 02:31:20 -0800 (PST) To: Btrfs BTRFS From: Psalle Subject: Deadlock while removing device, kernel 4.4.1 Message-ID: <56C2FA77.2010604@gmail.com> Date: Tue, 16 Feb 2016 11:31:19 +0100 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Sender: linux-btrfs-owner@vger.kernel.org List-ID: This is a test system so I'm reporting in case this is unknown but no data at risk. This filesystem was created with a device (well, actually partition) /dev/sdb3, then /dev/sdc{2,3,4} were added, and finally I attempted to remove /dev/sdb3. No profiles were passed at any point. Briefly after starting the remove, which seemed to proceed fine according to fi show, I started a rsync involving around 8GB from another fs into the one being reshaped. Not sure if this could have been related; rsync never transferred anything. Source was a degraded raid5 with six devices, one of them missing. Soon everything requiring disk access froze. This was with latest ubuntu stable upstream, i.e. 4.4.1-040401-generic I rebooted without problems to mount the filesystems. As I write, I'm doing the same process with latest 15.10 kernel 4.2.0-27-generic, for the moment things going smoothly. Login as root I captured the dmesg. Here is the final bit: [ 600.114436] INFO: task D-Bus thread:7692 blocked for more than 120 seconds. [ 600.114438] Tainted: P OE 4.4.1-040401-generic #201601311534 [ 600.114440] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 600.114442] D-Bus thread D ffff88007e4bfde8 0 7692 2842 0x00000000 [ 600.114446] ffff88007e4bfde8 0000000000000000 ffffffff81e11500 ffff8800b0b65940 [ 600.114450] ffff88007e4c0000 ffff8800bf509e68 ffff8800bf509e80 ffff88007e4bff58 [ 600.114454] ffff8800b0b65940 ffff88007e4bfe00 ffffffff817f9b15 ffff8800b0b65940 [ 600.114458] Call Trace: [ 600.114461] [] schedule+0x35/0x80 [ 600.114464] [] rwsem_down_read_failed+0xe0/0x140 [ 600.114467] [] ? schedule_hrtimeout_range_clock+0x19/0x40 [ 600.114471] [] call_rwsem_down_read_failed+0x14/0x30 [ 600.114474] [] ? down_read+0x20/0x30 [ 600.114477] [] __do_page_fault+0x375/0x400 [ 600.114480] [] do_page_fault+0x22/0x30 [ 600.114483] [] page_fault+0x28/0x30 [ 600.114487] INFO: task BrowserBlocking:7697 blocked for more than 120 seconds. [ 600.114489] Tainted: P OE 4.4.1-040401-generic #201601311534 [ 600.114491] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 600.114493] BrowserBlocking D ffff88003565fbe0 0 7697 2842 0x00000000 [ 600.114497] ffff88003565fbe0 00000058c6dff62b ffff88011abf8000 ffff8800ae816600 [ 600.114501] ffff880035660000 00000000ffffff00 ffff8800ae816600 ffff8800ae816600 [ 600.114505] ffff8800a35c1c70 ffff88003565fbf8 ffffffff817f9b15 ffff8800a35c1cd8 [ 600.114509] Call Trace: [ 600.114512] [] schedule+0x35/0x80 [ 600.114534] [] btrfs_tree_read_lock+0xe6/0x140 [btrfs] [ 600.114538] [] ? wake_atomic_t_function+0x60/0x60 [ 600.114554] [] btrfs_read_lock_root_node+0x34/0x50 [btrfs] [ 600.114569] [] btrfs_search_slot+0x73f/0x9f0 [btrfs] [ 600.114574] [] ? crypto_shash_update+0x30/0xe0 [ 600.114593] [] btrfs_check_dir_item_collision+0x77/0x120 [btrfs] [ 600.114614] [] btrfs_rename2+0x130/0x7b0 [btrfs] [ 600.114618] [] ? generic_permission+0x110/0x190 [ 600.114622] [] vfs_rename+0x54a/0x870 [ 600.114626] [] ? security_path_rename+0x20/0xd0 [ 600.114630] [] SyS_rename+0x38b/0x3d0 [ 600.114634] [] entry_SYSCALL_64_fastpath+0x16/0x75 There's more before this but it looks similar. Known issue?