ZFS: zpool scrub lockup

Andriy Gapon avg at icyb.net.ua
Thu Jul 9 17:35:10 UTC 2009

on 09/07/2009 20:21 Thomas Ronner said the following:
> I put the following in my kernel config:
> # debugging
> options         KDB
> options         DDB
> options         GDB
> options         BREAK_TO_DEBUGGER
> options         INVARIANTS
> options         INVARIANT_SUPPORT
> options         WITNESS
> options         WITNESS_KDB
> options         DEBUG_VFS_LOCKS
> options         DIAGNOSTIC
> options         SW_WATCHDOG
> When I send a BREAK from my serial console it enters the debugger, so
> that works. But when I start ZFS (/etc/rc.d/zfs start) it freezes again
> and BREAK doesn't enter the debugger. I'll try playing with the watchdog
> now, but I doubt this will help. Any clues?

For watchdog to fire it first needs to be enabled, e.g. by starting watchdogd.
Try to run /etc/rd.d/watchdogd onestart before zfs start and then wait for about
16 seconds (default timeout).
If that doesn't help, then it seems that the only option would be debugging via
serial console. Or manually generating NMI, if your system has an NMI

Andriy Gapon

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