Looks like the same issue kcompactd and btrfs-transaction locking up. Can not immediately reproduce, seemingly takes ~2weeks to appear. More problematic systems generally also have higher disk i/o, all btrfs.
%Cpu0 : 3.8 us, 1.3 sy, 0.0 ni, 0.0 id, 94.9 wa, 0.0 hi, 0.0 si, 0.0 st %Cpu1 : 1.3 us, 2.6 sy, 0.0 ni, 96.1 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st %CPU PID TID TIME STAT RSS SZ F COMMAND 0.0 27 27 00:00:03 D 0 0 1 [kcompactd0] 0.0 618 618 00:03:04 D 0 0 1 [btrfs-transacti] cat /proc/27/stack [<0>] __lock_page+0xff/0x140 [<0>] migrate_pages+0x91f/0xb80 [<0>] compact_zone+0x681/0x950 [<0>] kcompactd_do_work+0xfe/0x2a0 [<0>] kcompactd+0x86/0x1c0 [<0>] kthread+0x121/0x140 [<0>] ret_from_fork+0x35/0x40 [<0>] 0xffffffffffffffff cat /proc/618/stack [<0>] lock_extent_buffer_for_io+0x100/0x2a0 [btrfs] [<0>] btree_write_cache_pages+0x1b8/0x420 [btrfs] [<0>] btree_writepages+0x5d/0x70 [btrfs] [<0>] do_writepages+0x4b/0xe0 [<0>] __filemap_fdatawrite_range+0xcf/0x100 [<0>] filemap_fdatawrite_range+0x13/0x20 [<0>] btrfs_write_marked_extents+0x68/0x140 [btrfs] [<0>] btrfs_write_and_wait_marked_extents.constprop.20+0x4f/0x90 [btrfs] [<0>] btrfs_commit_transaction+0x696/0x910 [btrfs] [<0>] transaction_kthread+0x18d/0x1b0 [btrfs] [<0>] kthread+0x121/0x140 [<0>] ret_from_fork+0x35/0x40 [<0>] 0xffffffffffffffff INFO: task kcompactd0:27 blocked for more than 120 seconds. Tainted: P E 4.15.0-122-generic #124-Ubuntu "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kcompactd0 D 0 27 2 0x90000000 Call Trace: __schedule+0x24e/0x880 schedule+0x2c/0x80 io_schedule+0x16/0x40 __lock_page+0xff/0x140 ? page_cache_tree_insert+0xe0/0xe0 migrate_pages+0x91f/0xb80 ? __ClearPageMovable+0x10/0x10 ? isolate_freepages_block+0x3b0/0x3b0 compact_zone+0x681/0x950 kcompactd_do_work+0xfe/0x2a0 ? __switch_to_asm+0x35/0x70 ? __switch_to_asm+0x41/0x70 kcompactd+0x86/0x1c0 ? kcompactd+0x86/0x1c0 ? wait_woken+0x80/0x80 kthread+0x121/0x140 ? kcompactd_do_work+0x2a0/0x2a0 ? kthread_create_worker_on_cpu+0x70/0x70 ret_from_fork+0x35/0x40 ~ -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1891773 Title: kcompactd0 and btrfs-transaction keep deadlocking with each other To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1891773/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs