sleeping thread panic?

[Michael Butler]

Sorry, no symbols but this happened twice last night while being the
target of a dump over NFS ..

root at mail:/var/crash # less info.0
Dump header from device /dev/ada0s1
  Architecture: i386
  Architecture Version: 2
  Dump Length: 252809216B (241 MB)
  Blocksize: 512
  Dumptime: Sun Jul  8 00:21:23 2012
  Hostname: mail.auburn.protected-networks.net
  Magic: FreeBSD Kernel Dump
  Version String: FreeBSD 10.0-CURRENT #87: Sat Jul  7 22:39:55 EDT 2012
    root at mail.auburn.protected-networks.net:/usr/obj/usr/src/sys/AUBURN
  Panic String: sleeping thread
  Dump Parity: 2996346376
  Bounds: 0
  Dump Status: good


(kgdb) bt
#0  0xc07530cd in doadump ()
#1  0xc0753656 in kern_reboot ()
#2  0xc0753cfc in panic ()
#3  0xc079a34e in propagate_priority ()
#4  0xc079b5e4 in turnstile_wait ()
#5  0xc073ea71 in _mtx_lock_sleep ()
#6  0xc09c4772 in vm_page_unwire ()
#7  0xc07db039 in vfs_vmio_release ()
#8  0xc07dd476 in getnewbuf ()
#9  0xc07de50b in getblk ()
#10 0xc0966d99 in ffs_balloc_ufs2 ()
#11 0xc099281e in ffs_write ()
#12 0xc0a38b05 in VOP_WRITE_APV ()
#13 0xc068a65e in nfsvno_write ()
#14 0xc06882e7 in nfsrvd_write ()
#15 0xc066ea05 in nfsrvd_dorpc ()
#16 0xc067d42f in nfssvc_program ()
#17 0xc09356e2 in svc_run_internal ()
#18 0xc0935b70 in svc_thread_start ()
#19 0xc07204fb in fork_exit ()
#20 0xc09fe7a4 in fork_trampoline ()