[lustre-discuss] Kernel Panic on Snapshot Mount

[Robert Redl]

Good morning!

as there was no reaction, I try to change my question: Is anyone already
using 2.11.0 with ZFS and snapshots successfully?

My problem was temporally solved by downgrading the servers to 2.10.3.
Snapshots are now working again as expected and can be mounted without
any problems.

Best regards,
Robert

On 04/19/2018 04:26 PM, Robert Redl wrote:
> Dear All,
>
> today, I updated from Lustre 2.10.3 to 2.11.0 (on centos 7.4). The
> update is now finished on all servers and everything seems to work fine.
> However, when I try to mount a snapshot (we use the ZFS-backend), this
> results immediately in a crash of all servers:
>
> Apr 19 16:02:45 server1 kernel: Lustre: 58ffd1e-MDT0000: set dev_rdonly
> on this device
> Apr 19 16:02:45 server1 kernel: LustreError:
> 14660:0:(lu_object.c:1178:lu_device_fini()) ASSERTION(
> atomic_read(&d->ld_ref) == 0 ) failed: Refcount is 1
> Apr 19 16:02:45 server1 kernel: LustreError:
> 14660:0:(lu_object.c:1178:lu_device_fini()) LBUG
> Apr 19 16:02:45 server1 kernel: Pid: 14660, comm: mount.lustre
> Apr 19 16:02:45 server1 kernel:
>                                                                     
> Call Trace:
> Apr 19 16:02:45 server1 kernel:  [<ffffffffc06557ae>]
> libcfs_call_trace+0x4e/0x60 [libcfs]
> Apr 19 16:02:45 server1 kernel:  [<ffffffffc065583c>]
> lbug_with_loc+0x4c/0xb0 [libcfs]
> Apr 19 16:02:45 server1 kernel:  [<ffffffffc0b5502b>]
> lu_device_fini+0xbb/0xc0 [obdclass]
>
> Message from syslogd at met-ha-filer05a at Apr 19 16:02:45 ...
>  kernel:LustreError: 14660:0:(lu_object.c:1178:lu_device_fini())
> ASSERTION( atomic_read(&d->ld_ref) == 0 ) failed: Refcount is 1
> Apr 19 16:02:45 server1 kernel:  [<ffffffffc0b59fae>]
> dt_device_fini+0xe/0x10 [obdclass]
> Apr 19 16:02:45 server1 kernel:  [<ffffffffc0da2ea8>]
> osd_device_alloc+0x278/0x3b0 [osd_zfs]
> Apr 19 16:02:45 server1 kernel:  [<ffffffffc0b43f7a>]
> obd_setup+0x11a/0x2b0 [obdclass]
>
> Message from syslogd at met-ha-filer05a at Apr 19 16:02:45 ...
>  kernel:LustreError: 14660:0:(lu_object.c:1178:lu_device_fini()) LBUG
> Apr 19 16:02:45 server1 kernel:  [<ffffffffc0b443b8>]
> class_setup+0x2a8/0x840 [obdclass]
> Apr 19 16:02:45 server1 kernel:  [<ffffffffc0b4882c>]
> class_process_config+0x1b5c/0x2810 [obdclass]
> Apr 19 16:02:45 server1 kernel:  [<ffffffff81333563>] ?
> number.isra.2+0x323/0x360
> Apr 19 16:02:45 server1 kernel:  [<ffffffffc0b4c738>]
> do_lcfg+0x258/0x500 [obdclass]
> Apr 19 16:02:45 server1 kernel:  [<ffffffffc0b50f88>]
> lustre_start_simple+0x88/0x210 [obdclass]
> Apr 19 16:02:45 server1 kernel:  [<ffffffffc0b7dfba>]
> server_fill_super+0xf3a/0x1860 [obdclass]
> Apr 19 16:02:45 server1 kernel:  [<ffffffffc0660e27>] ?
> libcfs_debug_msg+0x57/0x80 [libcfs]
> Apr 19 16:02:45 server1 kernel:  [<ffffffffc0b54228>]
> lustre_fill_super+0x328/0x950 [obdclass]
> Apr 19 16:02:45 server1 kernel:  [<ffffffffc0b53f00>] ?
> lustre_fill_super+0x0/0x950 [obdclass]
> Apr 19 16:02:45 server1 kernel:  [<ffffffff8120948f>] mount_nodev+0x4f/0xb0
> Apr 19 16:02:45 server1 kernel:  [<ffffffffc0b4c148>]
> lustre_mount+0x38/0x60 [obdclass]
> Apr 19 16:02:45 server1 kernel:  [<ffffffff81209f1e>] mount_fs+0x3e/0x1b0
> Apr 19 16:02:45 server1 kernel:  [<ffffffff81226d57>]
> vfs_kern_mount+0x67/0x110
> Apr 19 16:02:45 server1 kernel:  [<ffffffff81229263>] do_mount+0x233/0xaf0
> Apr 19 16:02:45 server1 kernel:  [<ffffffff8118bb0e>] ?
> __get_free_pages+0xe/0x40
> Apr 19 16:02:45 server1 kernel:  [<ffffffff81229ea6>] SyS_mount+0x96/0xf0
> Apr 19 16:02:45 server1 kernel:  [<ffffffff816c0715>]
> system_call_fastpath+0x1c/0x21
> Apr 19 16:02:45 server1 kernel:
> Apr 19 16:02:45 server1 kernel: Kernel panic - not syncing: LBUG
>
>
>
> I'm posting this here as I don't have an account for the actual bug tracker.
> Has someone experienced a similar issue?
>
> Best regards
> Robert
>

-- 

Dr. Robert Redl geb. Schuster
Scientific Programmer, "Waves to Weather" (SFB/TRR165)
Meteorologisches Institut
Ludwig-Maximilians-Universität München
Theresienstr. 37, 80333 München, Germany
Tel.: +49 89 2180 4569

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