zfs page fault

[Dan Cojocar]

Hello,
I have found this morning that one of my systems was not responding.
After attaching a monitor I have found that the system has encountered
a page fault.
Here is the bt:
Fatal trap 12: page fault while in kernel mode
fault virtual address   = 0x4c
fault code              = supervisor write, protection violation
instruction pointer     = 0x20:0x8051ba96
stack pointer           = 0x28:0x83a8db7c
frame pointer           = 0x28:0x83a8db94
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         = 18 (vnlru)
Physical memory: 1015 MB
Dumping 273 MB: 258 242 226 210 194 178 162 146 130 114 98 82 66 50 34 18 2
#0  doadump () at pcpu.h:246
246             __asm __volatile("movl %%fs:0,%0" : "=r" (td));
(kgdb) bt
#0  doadump () at pcpu.h:246
#1  0x80477e99 in db_fncall (dummy1=-2086086336, dummy2=0,
dummy3=-2139548352, dummy4=0x83a8d920 "ÃyI\200\200ÈÄ\203") at
/usr/src/sys/ddb/db_command.c:548
#2  0x80478291 in db_command (last_cmdp=0x8073531c, cmd_table=0x0,
dopager=1) at /usr/src/sys/ddb/db_command.c:445
#3  0x804783ea in db_command_loop () at /usr/src/sys/ddb/db_command.c:498
#4  0x8047a23c in db_trap (type=12, code=0) at /usr/src/sys/ddb/db_main.c:229
#5  0x8053df03 in kdb_trap (type=12, code=0, tf=0x83a8db3c) at
/usr/src/sys/kern/subr_kdb.c:534
#6  0x806a804f in trap_fatal (frame=0x83a8db3c, eva=76) at
/usr/src/sys/i386/i386/trap.c:920
#7  0x806a8310 in trap_pfault (frame=0x83a8db3c, usermode=0, eva=76)
at /usr/src/sys/i386/i386/trap.c:842
#8  0x806a8ce5 in trap (frame=0x83a8db3c) at /usr/src/sys/i386/i386/trap.c:522
#9  0x8069062b in calltrap () at /usr/src/sys/i386/i386/exception.s:165
#10 0x8051ba96 in _sx_xlock (sx=0x3c, opts=0, file=0x80969370
"/usr/src/sys/modules/zfs/../../cddl/contrib/opensolaris/uts/common/fs/zfs/dbuf.c",
line=1807)
    at atomic.h:153
#11 0x80899235 in dmu_buf_update_user () from /boot/kernel/zfs.ko
#12 0x808f0a53 in zfs_znode_dmu_fini () from /boot/kernel/zfs.ko
#13 0x809136d6 in zfs_freebsd_reclaim () from /boot/kernel/zfs.ko
#14 0x806b3132 in VOP_RECLAIM_APV (vop=0x80975580, a=0x83a8dc30) at
vnode_if.c:1619
#15 0x80591b22 in vgonel (vp=0x874c4d9c) at vnode_if.h:830
#16 0x80596f13 in vnlru_free (count=245) at /usr/src/sys/kern/vfs_subr.c:899
#17 0x8059759e in vnlru_proc () at /usr/src/sys/kern/vfs_subr.c:768
#18 0x804f0f4f in fork_exit (callout=0x80597500 <vnlru_proc>, arg=0x0,
frame=0x83a8dd38) at /usr/src/sys/kern/kern_fork.c:821
#19 0x806906a0 in fork_trampoline () at /usr/src/sys/i386/i386/exception.s:270
(kgdb)

If someone needs more details I'm here.
Thanks,
Dan