Public bug reported:
I'm seeing messages like this in dmesg: [ 2400.951071] INFO: task btrfs-cleaner:325 blocked for more than 120 seconds. [ 2400.958293] Not tainted 4.4.0-24-generic #43-Ubuntu [ 2400.963918] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 2400.972037] btrfs-cleaner D ffff880071f77ce8 0 325 2 0x00000000 [ 2400.972049] ffff880071f77ce8 ffff8800045ac020 ffff88007a110c80 ffff88007d4b1900 [ 2400.972062] ffff880071f78000 ffff88007e31b9f0 ffff88007e31b800 ffff88007e31b9f0 [ 2400.972073] 0000000000000001 ffff880071f77d00 ffffffff81821b15 ffff880079a97950 [ 2400.972088] Call Trace: [ 2400.972103] [<ffffffff81821b15>] schedule+0x35/0x80 [ 2400.972163] [<ffffffffc0262fb3>] wait_current_trans.isra.21+0xd3/0x120 [btrfs] [ 2400.972174] [<ffffffff810c3b80>] ? wake_atomic_t_function+0x60/0x60 [ 2400.972225] [<ffffffffc02648db>] start_transaction+0x2cb/0x4c0 [btrfs] [ 2400.972276] [<ffffffffc0264ae8>] btrfs_start_transaction+0x18/0x20 [btrfs] [ 2400.972324] [<ffffffffc024d27f>] btrfs_drop_snapshot+0x54f/0x830 [btrfs] [ 2400.972334] [<ffffffff81821466>] ? __schedule+0x3b6/0xa30 [ 2400.972385] [<ffffffffc0263ae2>] btrfs_clean_one_deleted_snapshot+0xb2/0x100 [btrfs] [ 2400.972435] [<ffffffffc025c3af>] cleaner_kthread+0xcf/0x220 [btrfs] [ 2400.972484] [<ffffffffc025c2e0>] ? check_leaf+0x360/0x360 [btrfs] [ 2400.972493] [<ffffffff810a06a8>] kthread+0xd8/0xf0 [ 2400.972501] [<ffffffff810a05d0>] ? kthread_create_on_node+0x1e0/0x1e0 [ 2400.972509] [<ffffffff81825f8f>] ret_from_fork+0x3f/0x70 [ 2400.972517] [<ffffffff810a05d0>] ? kthread_create_on_node+0x1e0/0x1e0 Also, Sometimes btrfs quota rescan will stop making progress on this system and never recover until a reboot. ProblemType: Bug DistroRelease: Ubuntu 16.04 Package: linux-image-generic 4.4.0.24.25 ProcVersionSignature: Ubuntu 4.4.0-24.43-generic 4.4.10 Uname: Linux 4.4.0-24-generic x86_64 AlsaVersion: Advanced Linux Sound Architecture Driver Version k4.4.0-24-generic. AplayDevices: Error: [Errno 2] No such file or directory: 'aplay' ApportVersion: 2.20.1-0ubuntu2.1 Architecture: amd64 ArecordDevices: Error: [Errno 2] No such file or directory: 'arecord' AudioDevicesInUse: Error: command ['fuser', '-v', '/dev/snd/by-path', '/dev/snd/hwC0D1', '/dev/snd/pcmC0D3p', '/dev/snd/controlC0', '/dev/snd/seq', '/dev/snd/timer'] failed with exit code 1: Card0.Amixer.info: Error: [Errno 2] No such file or directory: 'amixer' Card0.Amixer.values: Error: [Errno 2] No such file or directory: 'amixer' Date: Tue Jun 14 08:40:00 2016 EcryptfsInUse: Yes IwConfig: Error: [Errno 2] No such file or directory: 'iwconfig' MachineType: NETGEAR ReadyNAS 314 ProcEnviron: TERM=screen PATH=(custom, no user) LANG=en_US.UTF-8 SHELL=/bin/bash ProcFB: 0 psbdrmfb ProcKernelCmdLine: ro rootflags=subvol=ubuntu console=tty0 console=ttyS0,115200n8 root=/dev/md127 RelatedPackageVersions: linux-restricted-modules-4.4.0-24-generic N/A linux-backports-modules-4.4.0-24-generic N/A linux-firmware 1.157 RfKill: Error: [Errno 2] No such file or directory: 'rfkill' SourcePackage: linux UpgradeStatus: Upgraded to xenial on 2016-06-02 (12 days ago) dmi.bios.date: 11/05/2013 dmi.bios.vendor: American Megatrends Inc. dmi.bios.version: 4.6.5 dmi.board.asset.tag: To be filled by O.E.M. dmi.board.name: To be filled by O.E.M. dmi.board.vendor: To be filled by O.E.M. dmi.board.version: To be filled by O.E.M. dmi.chassis.asset.tag: To Be Filled By O.E.M. dmi.chassis.type: 3 dmi.chassis.vendor: NETGEAR dmi.chassis.version: To Be Filled By O.E.M. dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvr4.6.5:bd11/05/2013:svnNETGEAR:pnReadyNAS314:pvr11/05/2013ReadyNAS-314V1.0:rvnTobefilledbyO.E.M.:rnTobefilledbyO.E.M.:rvrTobefilledbyO.E.M.:cvnNETGEAR:ct3:cvrToBeFilledByO.E.M.: dmi.product.name: ReadyNAS 314 dmi.product.version: 11/05/2013 ReadyNAS-314 V1.0 dmi.sys.vendor: NETGEAR ** Affects: linux (Ubuntu) Importance: Undecided Status: New ** Tags: amd64 apport-bug xenial -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1592461 Title: btrfs related kernel threads blocked and not making progress To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1592461/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs