bcache_writebac blocks and goes silent on trusty kernel 3.13.0-24-generic #47-Ubuntu
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
linux (Ubuntu) |
Fix Released
|
Medium
|
Unassigned | ||
Trusty |
Fix Released
|
Medium
|
Stefan Bader | ||
Utopic |
Fix Released
|
Medium
|
Unassigned |
Bug Description
We regularly use bcache to use SSDs as an extra block cache layer for performance on large working sets (archive mirrors, large databases, etc). Until now we have had good success with bcache on precise LTS with HWE kernels up to Saucy's.
Unfortunately when we mount a bcache-backed volume on a Trusty server, it immediately loses contact with bcache_writebac:
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
501 root 20 0 0 0 0 D 0.0 0.0 0:00.00 bcache_writebac
kern.log shows it losing its mind pretty much immediately on startup:
Aug 12 02:22:15 somehostname kernel: [ 6483.477618] md: bind<sdc>
Aug 12 02:22:15 somehostname kernel: [ 6483.478599] md: bind<sdd>
Aug 12 02:22:15 somehostname kernel: [ 6483.482016] md/raid0:md0: md_size is 781443072 sectors.
Aug 12 02:22:15 somehostname kernel: [ 6483.482024] md: RAID0 configuration for md0 - 1 zone
Aug 12 02:22:15 somehostname kernel: [ 6483.482026] md: zone0=[sdc/sdd]
Aug 12 02:22:15 somehostname kernel: [ 6483.482033] zone-offset= 0KB, device-offset= 0KB, size= 390721536KB
Aug 12 02:22:15 somehostname kernel: [ 6483.482036]
Aug 12 02:22:15 somehostname kernel: [ 6483.482055] md0: detected capacity change from 0 to 400098852864
Aug 12 02:22:15 somehostname kernel: [ 6483.487644] md0: unknown partition table
Aug 12 02:26:55 somehostname kernel: [ 6763.657249] bio: create slab <bio-2> at 2
Aug 12 02:26:55 somehostname kernel: [ 6763.658018] bcache: run_cache_set() invalidating existing data
Aug 12 02:26:55 somehostname kernel: [ 6763.695447] bcache: register_cache() registered cache device md0
Aug 12 02:26:55 somehostname kernel: [ 6763.696262] bcache: register_bdev() registered backing device sdb
Aug 12 02:26:55 somehostname kernel: [ 6763.697833] bcache: bch_cached_
Aug 12 02:27:24 somehostname kernel: [ 6793.114287] EXT4-fs (bcache0): mounted filesystem with ordered data mode. Opts: (null)
Aug 12 02:30:16 somehostname kernel: [ 6964.514425] INFO: task bcache_
Aug 12 02:30:16 somehostname kernel: [ 6964.608861] Not tainted 3.13.0-24-generic #47-Ubuntu
Aug 12 02:30:16 somehostname kernel: [ 6964.679403] "echo 0 > /proc/sys/
Aug 12 02:30:16 somehostname kernel: [ 6964.779270] bcache_writebac D ffff8817dfb34440 0 29721 2 0x00000000
Aug 12 02:30:16 somehostname kernel: [ 6964.779278] ffff882fafe57eb8 0000000000000002 ffff882fb100afe0 ffff882fafe57fd8
Aug 12 02:30:16 somehostname kernel: [ 6964.779286] 0000000000014440 0000000000014440 ffff882fb100afe0 ffff882fb7bcac80
Aug 12 02:30:16 somehostname kernel: [ 6964.779293] ffff882fb11c0000 ffffffffa03f5840 0000000000000000 0000000000000000
Aug 12 02:30:16 somehostname kernel: [ 6964.779301] Call Trace:
Aug 12 02:30:16 somehostname kernel: [ 6964.779335] [<ffffffffa03f5
Aug 12 02:30:16 somehostname kernel: [ 6964.779346] [<ffffffff81719
Aug 12 02:30:16 somehostname kernel: [ 6964.779356] [<ffffffff8108b
Aug 12 02:30:16 somehostname kernel: [ 6964.779368] [<ffffffff8108b
Aug 12 02:30:16 somehostname kernel: [ 6964.779379] [<ffffffff81726
Aug 12 02:30:16 somehostname kernel: [ 6964.779385] [<ffffffff8108b
Aug 12 02:32:16 somehostname kernel: [ 7084.828482] INFO: task bcache_
Aug 12 02:32:16 somehostname kernel: [ 7084.922987] Not tainted 3.13.0-24-generic #47-Ubuntu
Aug 12 02:32:16 somehostname kernel: [ 7084.993239] "echo 0 > /proc/sys/
Aug 12 02:32:16 somehostname kernel: [ 7085.093858] bcache_writebac D ffff8817dfb34440 0 29721 2 0x00000000
Aug 12 02:32:16 somehostname kernel: [ 7085.093866] ffff882fafe57eb8 0000000000000002 ffff882fb100afe0 ffff882fafe57fd8
Aug 12 02:32:16 somehostname kernel: [ 7085.093874] 0000000000014440 0000000000014440 ffff882fb100afe0 ffff882fb7bcac80
Aug 12 02:32:16 somehostname kernel: [ 7085.093881] ffff882fb11c0000 ffffffffa03f5840 0000000000000000 0000000000000000
Aug 12 02:32:16 somehostname kernel: [ 7085.093897] Call Trace:
Aug 12 02:32:16 somehostname kernel: [ 7085.093918] [<ffffffffa03f5
Aug 12 02:32:16 somehostname kernel: [ 7085.093928] [<ffffffff81719
Aug 12 02:32:16 somehostname kernel: [ 7085.093944] [<ffffffff8108b
Aug 12 02:32:16 somehostname kernel: [ 7085.093950] [<ffffffff8108b
Aug 12 02:32:16 somehostname kernel: [ 7085.093959] [<ffffffff81726
Aug 12 02:32:16 somehostname kernel: [ 7085.093964] [<ffffffff8108b
ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: linux-image-
ProcVersionSign
Uname: Linux 3.13.0-33-generic x86_64
ApportVersion: 2.14.1-0ubuntu3.3
Architecture: amd64
AudioDevicesInUse:
USER PID ACCESS COMMAND
/dev/snd/
/dev/snd/
CurrentDesktop: Unity
Date: Fri Aug 15 11:08:19 2014
HibernationDevice: RESUME=
InstallationDate: Installed on 2014-05-29 (77 days ago)
InstallationMedia: Ubuntu 14.04 LTS "Trusty Tahr" - Release amd64 (20140417)
MachineType: LENOVO 20ALCTO1WW
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=
RelatedPackageV
linux-
linux-
linux-firmware 1.127.5
SourcePackage: linux
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 02/06/2014
dmi.bios.vendor: LENOVO
dmi.bios.version: GIET69WW (2.19 )
dmi.board.
dmi.board.name: 20ALCTO1WW
dmi.board.vendor: LENOVO
dmi.board.version: 0B98405 STD
dmi.chassis.
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.
dmi.modalias: dmi:bvnLENOVO:
dmi.product.name: 20ALCTO1WW
dmi.product.
dmi.sys.vendor: LENOVO
tags: | added: regression-release |
Changed in linux (Ubuntu): | |
importance: | Undecided → Medium |
status: | Confirmed → Triaged |
Changed in linux (Ubuntu Trusty): | |
importance: | Undecided → Medium |
status: | New → Triaged |
Changed in linux (Ubuntu Utopic): | |
status: | Triaged → Fix Committed |
Changed in linux (Ubuntu Trusty): | |
assignee: | nobody → Stefan Bader (smb) |
status: | Triaged → Fix Committed |
This change was made by a bot.