Kernel Panic in latest -CURRENT

The kernel will panic usually once every 24 hours or so or if I run a
buildworld. This only started happening in the last month or so.

The information I took from kgdb is below. If there are any other commands
you'd like me to run on gdb, just ask and I'll do further debugging for you.

Thanks!

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Unread portion of the kernel message buffer:
kernel trap 12 with interrupts disabled


Fatal trap 12: page fault while in kernel mode
fault virtual address   = 0x14
fault code              = supervisor read, page not present
instruction pointer     = 0x20:0xc063b008
stack pointer           = 0x28:0xe40d3bdc
frame pointer           = 0x28:0xe40d3bf8
code segment            = base 0x0, limit 0xfffff, type 0x1b
                        = DPL 0, pres 1, def32 1, gran 1
processor eflags        = resume, IOPL = 0
current process         = 32 (em0 taskq)
trap number             = 12
panic: page fault
Uptime: 57m9s
Physical memory: 1015 MB
Dumping 143 MB: 128 112 96 80 64 48 32 16

#0  doadump () at pcpu.h:195
195     pcpu.h: No such file or directory.
        in pcpu.h
(kgdb) bt
#0  doadump () at pcpu.h:195
#1  0xc060cb73 in boot (howto=260) at /usr/src/sys/kern/kern_shutdown.c:409
#2  0xc060cd6f in panic (fmt=Variable "fmt" is not available.
) at /usr/src/sys/kern/kern_shutdown.c:563
#3  0xc086954c in trap_fatal (frame=0xe40d3b9c, eva=20) at
/usr/src/sys/i386/i386/trap.c:870
#4  0xc0869e8c in trap (frame=0xe40d3b9c) at
/usr/src/sys/i386/i386/trap.c:276
#5  0xc0853afb in calltrap () at /usr/src/sys/i386/i386/exception.s:139
#6  0xc063b008 in propagate_priority (td=0xc3ab5e00) at
/usr/src/sys/kern/subr_turnstile.c:272
#7  0xc063b989 in turnstile_wait (ts=0xc3a9e6e0, owner=0xc3ab5e00,
queue=Variable "queue" is not available.
) at /usr/src/sys/kern/subr_turnstile.c:739
#8  0xc060140d in _mtx_lock_sleep (m=0xc0993228, tid=3284357632, opts=0,
file=0x0, line=0) at /usr/src/sys/kern/kern_mutex.c:395
#9  0xc04decd7 in em_handle_rxtx (context=0xc3b63000, pending=1) at
/usr/src/sys/dev/em/if_em.c:1477
#10 0xc0639e72 in taskqueue_run (queue=0xc3be1880) at
/usr/src/sys/kern/subr_taskqueue.c:255
#11 0xc063a04f in taskqueue_thread_loop (arg=0xc3b632ec) at
/usr/src/sys/kern/subr_taskqueue.c:374
#12 0xc05ee896 in fork_exit (callout=0xc0639fd0 <taskqueue_thread_loop>,
arg=0xc3b632ec, frame=0xe40d3d38)
    at /usr/src/sys/kern/kern_fork.c:797
#13 0xc0853b70 in fork_trampoline () at
/usr/src/sys/i386/i386/exception.s:205
(kgdb) list *0xc063b008
0xc063b008 is in propagate_priority
(/usr/src/sys/kern/subr_turnstile.c:273).
268                     ts = td->td_blocked;
269                     MPASS(ts != NULL);
270                     MPASS(td->td_lock == &ts->ts_lock);
271                     /* Resort td on the list if needed. */
272                     if (!turnstile_adjust_thread(ts, td)) {
273                             mtx_unlock_spin(&ts->ts_lock);
274                             return;
275                     }
276                     /* The thread lock is released as ts lock above. */
277             }
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