odd panics on -current recently

Been getting what appear to be the same panic for at least a week on 
-current. Enabled dumps and this is the best trace I can get. I don't have 
the panic message, and this trace doesn't make a lot of sense to me:

#0  doadump () at pcpu.h:165
165             __asm __volatile("movl %%fs:0,%0" : "=r" (td));
(kgdb) bt
#0  doadump () at pcpu.h:165
#1  0xc0706e40 in buf.1 ()
#2  0xc051bfee in boot (howto=260) at ../../../kern/kern_shutdown.c:397
#3  0xc051c416 in panic (fmt=0xc06b19aa "%s")
     at ../../../kern/kern_shutdown.c:553
#4  0xc0688e6c in trap_fatal (frame=0xd3c1dc40, eva=0)
     at ../../../i386/i386/trap.c:831
#5  0xc06883a9 in trap (frame=
       {tf_fs = -1068302328, tf_es = -1066401752, tf_ds = -1047068632, 
tf_edi = -1047265920, tf_esi = -1035014144, tf_ebp = 0, tf_isp = 
-742269844, tf_ebx = -1066355360, tf_edx = -1035014144, tf_ecx = 0, tf_eax 
= -2, tf_trapno = 12, tf_err = 0, tf_eip = -1068198526, tf_cs = 32, 
tf_eflags = 589954, tf_esp = -1035014144, tf_ss = 4}) at 
../../../i386/i386/trap.c:269
#6  0xc067674a in calltrap () at ../../../i386/i386/exception.s:139
(kgdb)

I can't seem to reproduce it on demand, but it's hit me at least 5 times 
today and seems to occurr most frequently when i have a shell script 
running that pipes the output from a "tail -f <log> | grep <pattern>". 
Does any of this look familiar to anyone? It's really starting to get 
irritating! Kernel config is below.



machine		i386
ident		CATALYST
maxusers	0

#####################################################################
# CPU OPTIONS

cpu		I686_CPU		# aka Pentium Pro(tm)
options 	CPU_ENABLE_SSE
options 	CPU_FASTER_5X86_FPU
makeoptions	MODULES_OVERRIDE="acpi acpi/acpi_toshiba cpufreq aio linux cd9660 firewire firewire/sbp firewire/fwe firewire/fwip fdc fxp mii wlan rc4 wlan_wep ath ath_hal ath_rate_onoe md msdosfs ntfs usb umass sound/sound sound/driver/t4dwave linprocfs nfsclient nfsserver"
#makeoptions	MODULES_OVERRIDE="acpi acpi/acpi_toshiba cpufreq aio linux cd9660 fdc md msdosfs ntfs usb umass sound/sound sound/driver/t4dwave linprocfs nfsclient nfsserver if_tap netgraph/netgraph netgraph/ether netgraph/bridge netgraph/socket"

#options 	BLKDEV_IOSIZE=8192
options 	PQ_CACHESIZE=512	# color for 512k/16k cache
options 	INCLUDE_CONFIG_FILE     # Include this file in kernel
options 	CLK_USE_I8254_CALIBRATION

#####################################################################
# Scheduler options:
#
options 	SCHED_4BSD
#options 	SCHED_ULE
options 	PREEMPTION

#####################################################################
# COMPATIBILITY OPTIONS

options 	COMPAT_43
options 	COMPAT_FREEBSD4
options		SYSVMSG

options		SYSVSHM
options		SHMMAXPGS=65536
options		SHMSEG=256

options		SYSVSEM
options		SHMMNI=256
options		SEMMNS=512
options		SEMMNU=256

#####################################################################
# DEBUGGING OPTIONS

options 	KTRACE			#kernel tracing
#options 	INVARIANTS
#options 	INVARIANT_SUPPORT
#options 	WITNESS

#####################################################################
# NETWORKING OPTIONS

options 	INET			#Internet communications protocols

device		ether			#Generic Ethernet
device		loop			#Network loopback device
device		mem			# Memory and kernel memory devices
device		io			# I/O device
device		bpf			#Berkeley packet filter
device		random

options 	IPFILTER		#ipfilter support
options 	IPFILTER_LOG		#ipfilter logging

options 	IPSTEALTH		#support for stealth forwarding

options 	ZERO_COPY_SOCKETS

#####################################################################
# FILESYSTEM OPTIONS

options 	FFS			#Fast filesystem

options 	PROCFS			#Process filesystem (requires PSEUDOFS)
options 	PSEUDOFS		#Pseudo-filesystem framework
options 	SOFTUPDATES

options 	UFS_ACL
options 	UFS_DIRHASH

options 	MD_ROOT
options 	QUOTA			#enable disk quotas

#options 	SUIDDIR

#####################################################################
# POSIX P1003.1B

options 	_KPOSIX_PRIORITY_SCHEDULING
options		P1003_1B_SEMAPHORES

#####################################################################
# CLOCK OPTIONS

#options 	HZ=100
#options 	NTIMECOUNTER=20
options 	PPS_SYNC

#####################################################################
# SCSI DEVICES

device		scbus		#base SCSI code
device		da		#SCSI direct access devices (aka disks)
device		cd		#SCSI CD-ROMs
device		pass		#CAM passthrough driver

#####################################################################
# MISCELLANEOUS DEVICES AND OPTIONS

device		pty		#Pseudo ttys
device		md		#Memory/malloc disk

#####################################################################
# HARDWARE BUS CONFIGURATION

device		isa
device		pci
device		agp

#####################################################################
# HARDWARE DEVICE CONFIGURATION

device		atkbdc
device		atkbd
options 	KBD_INSTALL_CDEV	# install a CDEV entry in /dev

device		psm
options 	PSM_HOOKRESUME		#hook the system resume event, useful
options 	PSM_RESETAFTERSUSPEND	#reset the device at the resume event

device		vga
options 	VESA

device		npx

device		sc
options 	SC_ALT_MOUSE_IMAGE	# simplified mouse cursor in text mode
options 	SC_PIXEL_MODE		# add support for the raster text mode

device		ata
device		atadisk		# ATA disk drives
device		atapicd		# ATAPI CDROM drives

options 	GEOM_BDE		# Disk encryption.
options 	GEOM_BSD		# BSD disklabels
options 	GEOM_CONCAT		# Disk concatenation.
options 	GEOM_GATE		# Userland services.
options 	GEOM_GPT		# GPT partitioning
options 	GEOM_LABEL		# Providers labelization.
options 	GEOM_MBR		# DOS/MBR partitioning
options 	GEOM_VOL		# Volume names from UFS superblock

device		uart
#device		sio
options 	BREAK_TO_DEBUGGER	# A BREAK on a serial console goes to
 					# ddb, if available.
device		ppc
device		ppbus
device		lpt

device		cbb
device		pccard
device		cardbus
options 	POWERFAIL_NMI	# make it beep instead of panicing
device		pmtimer			# Adjust system timer at wakeup time