FreeBSD iSCSI panic

I woke up today to find a console with:

panic: _mtx_lock_sleep: recursed on non-recursive mutex iscsi-io @ /usr/src/sys/modules/iscsi/initiator/../../../dev/iscsi/initiator/isc_sm.c:324

The initiator is a FreeBSD-current amd64 from 8 May 2011. The iSCSI target is an inexpensive iomega NAS. Other hosts attached to this iSCSI NAS have also had errors, though. The errors clear when I reboot the NAS.

Unfortunately, the FreeBSD box is a diskless system. Dumps aren't exactly simple. While I heard...