panic on 8.0 when mounting r/o msdosfs media?

Hi,

on my i386 8.0 box (20070717) I get the attached panic when trying to mount, without
the -o ro option, a readonly msdosfs media, in this case a micro-SD card inside an
adapter inside a USB card reader.

I can succesfully mount the card readonly with the -o ro option (tested on a few days
older CURRENT).

I'll keep the full dump around.

Regards,
Rene
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Script started on Wed Oct 24 23:05:14 2007
root_at_195-241-214-37:/var/crash#kgdb -n 37

[GDB will not be able to debug user-mode threads: /usr/lib/libthread_db.so: Undefined symbol "ps_pglobal_lookup"]
GNU gdb 6.1.1 [FreeBSD]
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GDB is free software, covered by the GNU General Public License, and you are
welcome to change it and/or distribute copies of it under certain conditions.
Type "show copying" to see the conditions.
There is absolutely no warranty for GDB.  Type "show warranty" for details.
This GDB was configured as "i386-marcel-freebsd".

Unread portion of the kernel message buffer:


Fatal trap 12: page fault while in kernel mode
cpuid = 1; apic id = 01
fault virtual address	= 0xdeadc112
fault code		= supervisor read, page not present
instruction pointer	= 0x20:0xc0487c14
stack pointer	        = 0x28:0xe56fbba4
frame pointer	        = 0x28:0xe56fbbec
code segment		= base 0x0, limit 0xfffff, type 0x1b
			= DPL 0, pres 1, def32 1, gran 1
processor eflags	= interrupt enabled, resume, IOPL = 0
current process		= 50 (syncer)
Physical memory: 2039 MB
Dumping 108 MB: 93 77 61 45 29 13

#0  doadump () at pcpu.h:195
195	pcpu.h: No such file or directory.
	in pcpu.h
(kgdb) bt f
#0  doadump () at pcpu.h:195
No locals.
#1  0xc044542b in db_fncall (dummy1=-445662772, dummy2=0, dummy3=582, 
    dummy4=0xe56fb938 "´tDÀ") at /usr/src/sys/ddb/db_command.c:486
	fn_addr = -1068702302
	args = {-1066759648, -1066759637, -1069258163, -1066759648, 
  -1066761888, 120, -445662740, -445662944, -1069257392, -445662788}
	nargs = 0
	retval = Variable "retval" is not available.
(kgdb) bt
#0  doadump () at pcpu.h:195
#1  0xc044542b in db_fncall (dummy1=-445662772, dummy2=0, dummy3=582, 
    dummy4=0xe56fb938 "´tDÀ") at /usr/src/sys/ddb/db_command.c:486
#2  0xc044595c in db_command_loop () at /usr/src/sys/ddb/db_command.c:401
#3  0xc0446f98 in db_trap (type=12, code=0) at /usr/src/sys/ddb/db_main.c:222
#4  0xc04f4e3e in kdb_trap (type=12, code=0, tf=0xe56fbb64)
    at /usr/src/sys/kern/subr_kdb.c:502
#5  0xc0627659 in trap_fatal (frame=0xe56fbb64, eva=3735929106)
    at /usr/src/sys/i386/i386/trap.c:863
#6  0xc062786d in trap_pfault (frame=0xe56fbb64, usermode=0, eva=3735929106)
    at /usr/src/sys/i386/i386/trap.c:785
#7  0xc062816c in trap (frame=0xe56fbb64) at /usr/src/sys/i386/i386/trap.c:463
#8  0xc060feab in calltrap () at /usr/src/sys/i386/i386/exception.s:139
#9  0xc0487c14 in g_io_request (bp=0xc5475dec, cp=0xc5114440)
    at /usr/src/sys/geom/geom_io.c:356
#10 0xc048d89f in g_vfs_strategy (bo=0xc56652e0, bp=0xd8ec8bf0)
    at /usr/src/sys/geom/geom_vfs.c:107
#11 0xc052fd37 in bufwrite (bp=0xd8ec8bf0) at buf.h:429
#12 0xc052c5cc in bawrite (bp=0xd8ec8bf0) at buf.h:417
#13 0xc0534052 in vop_stdfsync (ap=0xe56fbcd8)
    at /usr/src/sys/kern/vfs_default.c:440
#14 0xc047d48f in devfs_fsync (ap=0xe56fbcd8)
    at /usr/src/sys/fs/devfs/devfs_vnops.c:394
---Type <return> to continue, or q <return> to quit---
#15 0xc0632d56 in VOP_FSYNC_APV (vop=0xc06815e0, a=0xe56fbcd8)
    at vnode_if.c:1007
#16 0xc05411ef in sched_sync () at vnode_if.h:538
#17 0xc04b1621 in fork_exit (callout=0xc0540e5f <sched_sync>, arg=0x0, 
    frame=0xe56fbd38) at /usr/src/sys/kern/kern_fork.c:796
#18 0xc060ff20 in fork_trampoline () at /usr/src/sys/i386/i386/exception.s:205
(kgdb) q
root_at_195-241-214-37:/var/crash#^Dexit

Script done on Wed Oct 24 23:05:50 2007