``Fatal double fault'' when running nightly jobs, perhaps ZFS-related

Tim Stewart tim at stoo.org
Fri Jun 24 13:44:16 UTC 2011

On 06/23/11 01:30 PM, Tim Stewart wrote:
> Hello,
> I have a FreeBSD 8.2-RELEASE-p2 system that uses ZFS, including booting.
>    The kernel is locally compiled and is just the GENERIC configuration
> with DTrace enabled and a MFI driver patch from the mailing list post at
> [1].
> The system panicked with a ``Fatal double fault'' at 3:09 AM one night
> (typed in manually from a screenshot, but proofread):
> Fatal double fault
> rip = 0xffffffff805d3eeb
> rsp = 0xffffff848585b000
> rbp = 0xffffff848585b020
> cpuid = 0; apic id = 20
> panic: double fault
> cpuid = 0
> KDB: stack backtrace
> #0 0xffffffff80618d3e at kdb_backtrace+0x5e
> #1 0xffffffff805e4d47 at panic+0x187
> #2 0xffffffff808dc834 at dblfault_handler+0xa4
> #3 0xffffffff808c53ad at Xdblfault+0xad
> Uptime: 3d11h11m37s
> Cannot dump. Device not defined or unavailable.
> Automatic reboot in 15 seconds - press a key on the console to abort
> Sleeping thread (tid 100141, pid 5) owns a non-sleepable lock
> It seems likely that the activity that prompted the fault is related to
> the nightly periodic jobs.  Others have suggested that it may be related
> to /etc/periodic/security/100.chksetuid (see [2] and [3]), as it does a
> find on every filesystem not marked as `nosuid.'  Indeed, I have a ZFS
> dataset containing 71+ million files that (at the time) was not marked
> as nosuid.
> I have not been able to replicate the issue since and it has only
> happened once.  I have set `setuid=off' on the large ZFS dataset so that
> 100.chksetuid will no longer traverse it every night.
> Any clue as to what is happening here?  I don't have a kernel core dump
> since I'm using ZFS for swap, though I can change this if it helps
> troubleshoot the issue in the event of another crash.
> Thanks for any help you can provide,

Would a different list be more appropriate for this inquiry?


Tim Stewart

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