panic: mutex rtentry not owned at /usr/src/sys/net/route.c:225

I had this panic on a 1 day old kernel. route.c is rev 1.87, nd6.c is
rev 1.31 and ip6_output.c is at rev 1.58.

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angel:/usr/obj/usr/src/sys/ANGEL # gdb -k kernel.debug /var/crash/vmcore.10 
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This GDB was configured as "i386-undermydesk-freebsd"...
panic: mutex rtentry not owned at /usr/src/sys/net/route.c:225
panic messages:
---
panic: mutex rtentry not owned at /usr/src/sys/net/route.c:225

syncing disks, buffers remaining... 2191 2191 2191 2191 2191 2191 2191 2191 2191 2191 2191 2191 2191 2191 2191 2191 2191 2191 2191 2191 
giving up on 1977 buffers
Uptime: 1d13h57m25s
Dumping 250 MB
 16 32 48 64 80 96 112 128 144 160 176 192 208 224 240
---
Reading symbols from /boot/kernel/if_xl.ko...done.
...
#0  doadump () at /usr/src/sys/kern/kern_shutdown.c:240
240             dumping++;
(kgdb) (kgdb) bt
#0  doadump () at /usr/src/sys/kern/kern_shutdown.c:240
#1  0xc0482757 in boot (howto=256) at /usr/src/sys/kern/kern_shutdown.c:372
#2  0xc0482a18 in panic () at /usr/src/sys/kern/kern_shutdown.c:550
#3  0xc047ad51 in _mtx_assert (m=0xc2a0da90, what=0, 
    file=0xc05b9e4f "/usr/src/sys/net/route.c", line=225)
    at /usr/src/sys/kern/kern_mutex.c:855
#4  0xc04e0598 in rtfree (rt=0xc2a0da00) at /usr/src/sys/net/route.c:225
#5  0xc0518291 in nd6_output (ifp=0xc2988800, origifp=0xc2988800, 
    m0=0xc12ae700, dst=0xc2a240dc, rt0=0xc361ca00)
    at /usr/src/sys/netinet6/nd6.c:1917
#6  0xc0513ad9 in ip6_output (m0=0x0, opt=0x0, ro=0xc2a64120, flags=0, 
    im6o=0x0, ifpp=0x0, inp=0xc2a640e4)
    at /usr/src/sys/netinet6/ip6_output.c:961
#7  0xc04fa5b2 in tcp_output (tp=0xc2a9a42c)
    at /usr/src/sys/netinet/tcp_output.c:883
#8  0xc04fe40d in tcp_timer_delack (xtp=0xc2a9a42c)
    at /usr/src/sys/netinet/tcp_timer.c:198
#9  0xc048fc66 in softclock (dummy=0x0) at /usr/src/sys/kern/kern_timeout.c:225
#10 0xc04728fb in ithread_loop (arg=0xc1298d00)
    at /usr/src/sys/kern/kern_intr.c:534
#11 0xc0471c9b in fork_exit (callout=0xc04727d0 <ithread_loop>, 
    arg=0xc1298d00, frame=0xcd77bd48) at /usr/src/sys/kern/kern_fork.c:796
(kgdb) 
##################################

John
-- 
John Hay -- John.Hay_at_icomtek.csir.co.za / jhay_at_FreeBSD.org