DragonFlyBSD

On 3.6-rel (x86_64) of 20th November (ac04afc3):
after doing NFS heavy use,
build(7) kernel w/ /usr/src & /usr/obj NFS mount,
reboot results in crash below.
Crash easy to reproduce: it happens every time.

Crash introduced during 1-2 month ago.

Same problem seen on i386 & master of 20th November 2013.

Crash dump on leaf: ~thomas/crash/bog.x86_64/7.

-
syncing disks... 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
done

Fatal trap 12: page fault while in kernel mode
cpuid = 0; lapic->id = 00000000
fault virtual address = 0x0
fault code = supervisor read data, page not present
instruction pointer = 0x8:0xffffffff803e3dad
stack pointer = 0x10:0xffffffe0d22c3368
frame pointer = 0x10:0xffffffe0d22c3428
code segment = base 0x0, limit 0xfffff, type 0x1b = DPL 0, pres 1, long 0, def32 0, gran 1
processor eflags = interrupt enabled, resume, IOPL = 0
current process = 79894
current thread = pri 31
kernel: type 12 trap, code=0

CPU0 stopping CPUs: 0x0000000e
stopped
..
(kgdb) bt
..
#13 0xffffffff803e6dec in nfs_removeit (sp=sp@entry=0xffffffe00f4ef668)
at /usr/src/sys/vfs/nfs/nfs_vnops.c:1840
#14 0xffffffff803cf38a in nfs_inactive (ap=0xffffffe0d22c3480)
at /usr/src/sys/vfs/nfs/nfs_node.c:402
#15 0xffffffff8035c476 in vop_inactive (ops=0xffffffe049764d00,
vp=vp@entry=0xffffffe0a3759880) at /usr/src/sys/kern/vfs_vopops.c:793
#16 0xffffffff8034c823 in vclean_vxlocked (vp=vp@entry=0xffffffe0a3759880,
flags=flags@entry=8) at /usr/src/sys/kern/vfs_subr.c:1231
#17 0xffffffff8034c9f0 in vgone_vxlocked (vp=vp@entry=0xffffffe0a3759880)
at /usr/src/sys/kern/vfs_subr.c:1428
#18 0xffffffff8034fe80 in vflush_scan (mp=mp@entry=0xffffffe0c8b7e700,
vp=0xffffffe0a3759880, data=data@entry=0xffffffe0d22c36d0)
at /usr/src/sys/kern/vfs_mount.c:1015
#19 0xffffffff803501b5 in vmntvnodescan (mp=mp@entry=0xffffffe0c8b7e700,
flags=flags@entry=2, fastfunc=fastfunc@entry=0x0,
slowfunc=slowfunc@entry=0xffffffff8034fde0 <vflush_scan>,
data=data@entry=0xffffffe0d22c36d0) at /usr/src/sys/kern/vfs_mount.c:826
#20 0xffffffff80350446 in vflush (mp=mp@entry=0xffffffe0c8b7e700, rootrefs=0,
rootrefs@entry=1, flags=flags@entry=2)
at /usr/src/sys/kern/vfs_mount.c:946
#21 0xffffffff803e1bfd in nfs_unmount (mp=0xffffffe0c8b7e700, mntflags=524288)
at /usr/src/sys/vfs/nfs/nfs_vfsops.c:1218
#22 0xffffffff8035db96 in vfs_unmount (mp=mp@entry=0xffffffe0c8b7e700,
mntflags=mntflags@entry=524288) at /usr/src/sys/kern/vfs_vfsops.c:134
#23 0xffffffff80354c4d in dounmount (mp=mp@entry=0xffffffe0c8b7e700,
flags=flags@entry=524288) at /usr/src/sys/kern/vfs_syscalls.c:785
#24 0xffffffff803496f8 in vfs_umountall_callback (mp=0xffffffe0c8b7e700,
data=<optimized out>) at /usr/src/sys/kern/vfs_subr.c:1797
#25 0xffffffff8034faf6 in mountlist_scan (
callback=callback@entry=0xffffffff803496db <vfs_umountall_callback>,
data=data@entry=0x0, how=how@entry=6) at /usr/src/sys/kern/vfs_mount.c:647
#26 0xffffffff8034c450 in vfs_unmountall ()
at /usr/src/sys/kern/vfs_subr.c:1786
#27 0xffffffff802d2f40 in boot (howto=0)
at /usr/src/sys/kern/kern_shutdown.c:357
#28 0xffffffff802d3474 in sys_reboot (uap=0xffffffe0d22c3950)
at /usr/src/sys/kern/kern_shutdown.c:186
..