nullfs panic with recent current

Trying to build world, having null mounted /usr/src & /usr/obj, i've got
this panic.

root_at_slave# uname -a
FreeBSD slave.rinet.ru 8.0-CURRENT FreeBSD 8.0-CURRENT #0 r182885: Tue Sep  9 22:52:56 MSD 2008     root_at_slave.rinet.ru:/usr/obj/usr/src/sys/slave-smp  amd64

root_at_slave# kgdb kernel.debug /var/crash/vmcore.7
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 "amd64-marcel-freebsd"...

Unread portion of the kernel message buffer:


Fatal trap 9: general protection fault while in kernel mode
cpuid = 0; apic id = 00
instruction pointer     = 0x8:0xffffffff80216e99
stack pointer           = 0x10:0xfffffffe6189d5a0
frame pointer           = 0x10:0xfffffffe6189d5d0
code segment            = base 0x0, limit 0xfffff, type 0x1b
                        = DPL 0, pres 1, long 1, def32 0, gran 1
processor eflags        = interrupt enabled, resume, IOPL = 0
current process         = 47776 (cc1)
panic: from debugger
cpuid = 0
Uptime: 19m15s
Physical memory: 998 MB
Dumping 156 MB: 141 125 109 93 77 61 45 29 13

Reading symbols from /boot/kernel/nullfs.ko...Reading symbols from /boot/kernel/nullfs.ko.symbols...done.
done.
Loaded symbols for /boot/kernel/nullfs.ko
Reading symbols from /boot/kernel/geom_mirror.ko...Reading symbols from /boot/kernel/geom_mirror.ko.symbols...done.
done.
Loaded symbols for /boot/kernel/geom_mirror.ko
Reading symbols from /boot/kernel/ipfw.ko...Reading symbols from /boot/kernel/ipfw.ko.symbols...done.
done.
Loaded symbols for /boot/kernel/ipfw.ko
Reading symbols from /boot/kernel/if_bge.ko...Reading symbols from /boot/kernel/if_bge.ko.symbols...done.
done.
Loaded symbols for /boot/kernel/if_bge.ko
Reading symbols from /boot/kernel/miibus.ko...Reading symbols from /boot/kernel/miibus.ko.symbols...done.
done.
Loaded symbols for /boot/kernel/miibus.ko
Reading symbols from /boot/kernel/if_em.ko...Reading symbols from /boot/kernel/if_em.ko.symbols...done.
done.
Loaded symbols for /boot/kernel/if_em.ko
Reading symbols from /boot/kernel/if_nfe.ko...Reading symbols from /boot/kernel/if_nfe.ko.symbols...done.
done.
Loaded symbols for /boot/kernel/if_nfe.ko
Reading symbols from /boot/kernel/if_vlan.ko...Reading symbols from /boot/kernel/if_vlan.ko.symbols...done.
done.
Loaded symbols for /boot/kernel/if_vlan.ko
#0  doadump () at pcpu.h:196
196             __asm __volatile("movq %%gs:0,%0" : "=r" (td));
(kgdb) l *0xffffffff80216e99
0xffffffff80216e99 is in _mtx_lock_flags (/usr/src/sys/kern/kern_mutex.c:174).
169     void
170     _mtx_lock_flags(struct mtx *m, int opts, const char *file, int line)
171     {
172
173             MPASS(curthread != NULL);
174             KASSERT(m->mtx_lock != MTX_DESTROYED,
175                 ("mtx_lock() of destroyed mutex _at_ %s:%d", file, line));
176             KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_sleep,
177                 ("mtx_lock() of spin mutex %s _at_ %s:%d", m->lock_object.lo_name,
178                 file, line));
(kgdb) bt
#0  doadump () at pcpu.h:196
#1  0xffffffff8022399a in boot (howto=260)
    at /usr/src/sys/kern/kern_shutdown.c:418
#2  0xffffffff80223e37 in panic (fmt=Variable "fmt" is not available.
) at /usr/src/sys/kern/kern_shutdown.c:572
#3  0xffffffff80176fa7 in db_panic (addr=Variable "addr" is not available.
) at /usr/src/sys/ddb/db_command.c:446
#4  0xffffffff801778f9 in db_command (last_cmdp=0xffffffff80530f88,
    cmd_table=0x0, dopager=1) at /usr/src/sys/ddb/db_command.c:413
#5  0xffffffff80177b20 in db_command_loop ()
    at /usr/src/sys/ddb/db_command.c:466
#6  0xffffffff80179469 in db_trap (type=Variable "type" is not available.
) at /usr/src/sys/ddb/db_main.c:228
#7  0xffffffff802511e0 in kdb_trap (type=9, code=0, tf=0xfffffffe6189d4f0)
    at /usr/src/sys/kern/subr_kdb.c:534
#8  0xffffffff8036671d in trap_fatal (frame=0xfffffffe6189d4f0, eva=Variable "eva" is not available.
)
    at /usr/src/sys/amd64/amd64/trap.c:754
#9  0xffffffff8036722a in trap (frame=0xfffffffe6189d4f0)
    at /usr/src/sys/amd64/amd64/trap.c:560
#10 0xffffffff8034a64e in calltrap ()
    at /usr/src/sys/amd64/amd64/exception.S:217
#11 0xffffffff80216e99 in _mtx_lock_flags (m=0xdeadc0dedeadc19e, opts=16,
    file=0xffffffff807caa40 "/usr/src/sys/modules/nullfs/../../fs/nullfs/null_vnops.c", line=532) at /usr/src/sys/kern/kern_mutex.c:173
#12 0xffffffff807c9e1c in null_lock (ap=0xfffffffe6189d670)
    at /usr/src/sys/modules/nullfs/../../fs/nullfs/null_vnops.c:532
#13 0xffffffff8038413b in VOP_LOCK1_APV (vop=0xffffffff807caee0,
    a=0xfffffffe6189d670) at vnode_if.c:1618
---Type <return> to continue, or q <return> to quit---
#14 0xffffffff802b41b7 in _vn_lock (vp=0xffffff001d7981d8, flags=524288,
    file=0xffffffff803bf0b2 "/usr/src/sys/kern/vfs_subr.c", line=2151)
    at vnode_if.h:839
#15 0xffffffff802a9570 in vrele (vp=0xffffff001d7981d8)
    at /usr/src/sys/kern/vfs_subr.c:2151
#16 0xffffffff8029e977 in namei (ndp=0xfffffffe6189da10)
    at /usr/src/sys/kern/vfs_lookup.c:226
#17 0xffffffff802b3aaa in vn_open_cred (ndp=0xfffffffe6189da10,
    flagp=0xfffffffe6189d95c, cmode=420, cred=0xffffff000173e800,
    fp=0xffffff00389661e0) at /usr/src/sys/kern/vfs_vnops.c:190
#18 0xffffffff802b21fe in kern_openat (td=0xffffff0001b736c0, fd=-100,
    path=0xc9ec80 <Address 0xc9ec80 out of bounds>, pathseg=Variable "pathseg" is not available.
)
    at /usr/src/sys/kern/vfs_syscalls.c:1069
#19 0xffffffff80366c76 in syscall (frame=0xfffffffe6189dc90)
    at /usr/src/sys/amd64/amd64/trap.c:898
#20 0xffffffff8034a85b in Xfast_syscall ()
    at /usr/src/sys/amd64/amd64/exception.S:338
#21 0x000000000084a53c in ?? ()
Previous frame inner to this frame (corrupt stack?)
(kgdb)


-- 
Oleg.

================================================================
=== Oleg Bulyzhin -- OBUL-RIPN -- OBUL-RIPE -- oleg_at_rinet.ru ===
================================================================