ZFS Kernel Panic on 10.0-RELEASE

Mon Jun 2 20:44:18 UTC 2014

----- Original Message ----- 
From: "Mike Carlson" <mike at bayphoto.com>
To: "Steven Hartland" <killing at multiplay.co.uk>; <freebsd-fs at freebsd.org>
Sent: Monday, June 02, 2014 9:15 PM
Subject: Re: ZFS Kernel Panic on 10.0-RELEASE


> On 6/2/2014 1:06 PM, Steven Hartland wrote:

>> I don't have a core.0.txt, I only have:
>>
>>      ~/p/z/dump> ls -al
>>    total 347690
>>    drwxr-xr-x  3 mikec  wheel              8 Jun  2 03:25 .
>>    drwxr-xr-x  4 mikec  wheel              5 Jun  2 10:44 ..
>>    drwxrwxr-x  2 mikec  operator           2 Jun  2 03:07 .snap
>>    -rw-r--r--  1 mikec  wheel              2 Jun  2 03:24 bounds
>>    -rw-------  1 mikec  wheel            446 Jun  2 03:24 info.0
>>    lrwxr-xr-x  1 mikec  wheel              6 Jun  2 03:25 info.last ->
>>    info.0
>>    -rw-------  1 mikec  wheel     3469885440 Jun  2 03:25 vmcore.0
>>    lrwxr-xr-x  1 mikec  wheel              8 Jun  2 03:25 vmcore.last
>>    -> vmcore.0
>>
>> But, here is the kgdb output (with backtrace):
>>
>>      ~/p/z/dump> cat ../kgdb_backtrace.txt
>>    <118>root@:/ # zfs set canmount=on zroot/data/working
>>    <118>root@:/ # zfs mount zroot/data/working
>>
>>
>>    Fatal trap 12: page fault while in kernel mode
>>    cpuid = 14; apic id = 22
>>    fault virtual address   = 0x4a0
>>    fault code              = supervisor read data, page not present
>>    instruction pointer     = 0x20:0xffffffff8185a39f
>>    stack pointer           = 0x28:0xfffffe1834608570
>>    frame pointer           = 0x28:0xfffffe18346085b0
>>    code segment            = base 0x0, limit 0xfffff, type 0x1b
>>                             = DPL 0, pres 1, long 1, def32 0, gran 1
>>    processor eflags        = interrupt enabled, resume, IOPL = 0
>>    current process         = 2 (txg_thread_enter)
>>    trap number             = 12
>>    panic: page fault
>>    cpuid = 14
>>    KDB: stack backtrace:
>>    #0 0xffffffff808e7ee0 at kdb_backtrace+0x60
>>    #1 0xffffffff808af9c5 at panic+0x155
>>    #2 0xffffffff80c8e7b2 at trap_fatal+0x3a2
>>    #3 0xffffffff80c8ea89 at trap_pfault+0x2c9
>>    #4 0xffffffff80c8e216 at trap+0x5e6
>>    #5 0xffffffff80c754b2 at calltrap+0x8
>>    #6 0xffffffff8182eb5a at dsl_dataset_block_kill+0x3a
>>    #7 0xffffffff8182b967 at dnode_sync+0x237
>>    #8 0xffffffff81823fcb at dmu_objset_sync_dnodes+0x2b
>>    #9 0xffffffff81823e4d at dmu_objset_sync+0x1ed
>>    #10 0xffffffff8183829a at dsl_pool_sync+0xca
>>    #11 0xffffffff81853a4e at spa_sync+0x52e
>>    #12 0xffffffff8185c925 at txg_sync_thread+0x375
>>    #13 0xffffffff80881a9a at fork_exit+0x9a
>>    #14 0xffffffff80c759ee at fork_trampoline+0xe
>>    Uptime: 26m15s
>>    Dumping 3309 out of 98234
>>    MB:..1%..11%..21%..31%..41%..51%..61%..71%..81%..91%
>>
>>    Reading symbols from /boot/kernel/zfs.ko.symbols...done.
>>    Loaded symbols for /boot/kernel/zfs.ko.symbols
>>    Reading symbols from /boot/kernel/opensolaris.ko.symbols...done.
>>    Loaded symbols for /boot/kernel/opensolaris.ko.symbols
>>    #0  doadump (textdump=<value optimized out>) at pcpu.h:219
>>    219             __asm("movq %%gs:%1,%0" : "=r" (td)
>>    (kgdb) backtrace
>>    #0  doadump (textdump=<value optimized out>) at pcpu.h:219
>>    #1  0xffffffff808af640 in kern_reboot (howto=260) at
>>    /usr/src/sys/kern/kern_shutdown.c:447
>>    #2  0xffffffff808afa04 in panic (fmt=<value optimized out>) at
>>    /usr/src/sys/kern/kern_shutdown.c:754
>>    #3  0xffffffff80c8e7b2 in trap_fatal (frame=<value optimized out>,
>>    eva=<value optimized out>) at /usr/src/sys/amd64/amd64/trap.c:882
>>    #4  0xffffffff80c8ea89 in trap_pfault (frame=0xfffffe18346084c0,
>>    usermode=0) at /usr/src/sys/amd64/amd64/trap.c:699
>>    #5  0xffffffff80c8e216 in trap (frame=0xfffffe18346084c0) at
>>    /usr/src/sys/amd64/amd64/trap.c:463
>>    #6  0xffffffff80c754b2 in calltrap () at
>>    /usr/src/sys/amd64/amd64/exception.S:232
>>    #7  0xffffffff8185a39f in bp_get_dsize_sync (spa=0xfffff80041835000,
>>    bp=0xfffffe001b8a1780)
>>         at
>> /usr/src/sys/modules/zfs/../../cddl/contrib/opensolaris/uts/common/fs/zfs/spa_misc.c:1635
>>    #8  0xffffffff8182eb5a in dsl_dataset_block_kill
>>    (ds=0xfffff800410fec00, bp=0xfffffe001b8a1780,
>>    tx=0xfffff8004faa0600, async=0)
>>         at
>> /usr/src/sys/modules/zfs/../../cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_dataset.c:129
>>    #9  0xffffffff8182b967 in dnode_sync (dn=0xfffff8004fe626c0,
>>    tx=0xfffff8004faa0600) at
>> /usr/src/sys/modules/zfs/../../cddl/contrib/opensolaris/uts/common/fs/zfs/dnode_sync.c:128
>>    #10 0xffffffff81823fcb in dmu_objset_sync_dnodes
>>    (list=0xfffff80041956b10, newlist=<value optimized out>, tx=<value
>>    optimized out>)
>>         at
>> /usr/src/sys/modules/zfs/../../cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_objset.c:945
>>    #11 0xffffffff81823e4d in dmu_objset_sync (os=0xfffff80041956800,
>>    pio=0xfffff800418c43b0, tx=0xfffff8004faa0600)
>>         at
>> /usr/src/sys/modules/zfs/../../cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_objset.c:1062
>>    #12 0xffffffff8183829a in dsl_pool_sync (dp=0xfffff8004183c000,
>>    txg=<value optimized out>)
>>         at
>> /usr/src/sys/modules/zfs/../../cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_pool.c:413
>>    #13 0xffffffff81853a4e in spa_sync (spa=0xfffff80041835000,
>>    txg=3373534) at
>> /usr/src/sys/modules/zfs/../../cddl/contrib/opensolaris/uts/common/fs/zfs/spa.c:6410
>>    #14 0xffffffff8185c925 in txg_sync_thread (arg=0xfffff8004183c000)
>>    at
>> /usr/src/sys/modules/zfs/../../cddl/contrib/opensolaris/uts/common/fs/zfs/txg.c:515
>>    #15 0xffffffff80881a9a in fork_exit (callout=0xffffffff8185c5b0
>>    <txg_sync_thread>, arg=0xfffff8004183c000, frame=0xfffffe1834608ac0)
>>    at /usr/src/sys/kern/kern_fork.c:995
>>    #16 0xffffffff80c759ee in fork_trampoline () at
>>    /usr/src/sys/amd64/amd64/exception.S:606
>>    #17 0x0000000000000000 in ?? ()
>>    Current language:  auto; currently minimal
>>
>>
>> If anyone wants to help out and check out the vmcore file, email me 
>> off the list and I'll provide a S3 url of the tar'd + xz file.
>>
>>
> Output of "frame 7":
>
>    (kgdb) frame 7
>    #7  0xffffffff8185a39f in bp_get_dsize_sync (spa=0xfffff80041835000,
>    bp=0xfffffe001b8a1780)
>         at
>    /usr/src/sys/modules/zfs/../../cddl/contrib/opensolaris/uts/common/fs/zfs/spa_misc.c:1635
>    1635                    dsize = (asize >> SPA_MINBLOCKSHIFT) *
>    vd->vdev_deflate_ratio;
>
> Is that what you were looking for?

Thats the line I gathered it was on but no I need to know what the value
of vd is, so what you need to do is:
print vd

If thats valid then:
print *vd

Given the panic I'm kind of expecting garbage or null (0x00)

> I'm not familar with this process, so I hope this does not become too 
> painful in pulling the details out.

No problem, everyone has to learn some time ;-)

 Regards
 Steve