ZFS kernel panic at zio_ddt_free

[Ka Man Tong]

Hi,

We are using FreeBSD 9.0 on amd64.
Recently we have encountered many kernel panic.
And now when the ZFS is mounted (and lastly re-imported using a fresh
installation of FreeBSD on i386),
the kernel hangs with the stack dump.

...
#6 0xc7490154 at zio_ddt_free+0x54
#7 0xc7490411 at zio_execute+0xa1
#8 0xc0a571ba at taskqueue_run_locked+0xca
#9 0xc0a580ac at taskqueue_thread_loop+0xbc
#10 0xc09ea997 at fork_exit+0x97
#11 0xc0d32b04 at fork_trampoline+0x8

After google for a while, it seems that the function zio_ddt_free is not
handled correctly.


http://mail.opensolaris.org/pipermail/zfs-discuss/2012-February/050972.html

We don't know whether our case is the same as the case in zfs-discuss group.
And we would like to take a try on the patch first.

Any help would be appreciated.  Thanks.