Bug 146037

I have VPN servers on mpd5.5

FreeBSD vpn3 8.0-STABLE FreeBSD 8.0-STABLE #2 r207058M: Thu Apr 22 15:40:40
EEST 2010     admin@vpn3:/usr/obj/usr/src/sys/GENERICVPN  i386

and every 5-10 minutes my billing system send mpd-limit CoA message to mpd.
Every 2-3 day server go into kernel panic:

Fatal trap 12: page fault while in kernel mode
cpuid = 3; apic id = 07
fault virtual address   = 0x24
fault code              = supervisor read, page not present
instruction pointer     = 0x20:0x8a04c9e4
stack pointer           = 0x28:0xee67386c
frame pointer           = 0x28:0xee673aa4
code segment            = base rx0, limit 0xfffff, type 0x1b
                        = DPL 0, pres 1, def32 1, gran 1
processor eflags        = interrupt enabled, resume, IOPL = 0
current process         = 871 (mpd5)
trap number             = 12
panic: page fault
cpuid = 3
Uptime: 2d7h39m7s
Physical memory: 2035 MB
Dumping 390 MB: 375 359 343

Fatal trap 12: page fault while in kernel mode
cpuid = 2; apic id = 06
fault virtual address   = 0x0
fault code              = supervisor write, page not present
instruction pointer     = 0x20:0x8a04c7cb
stack pointer           = 0x28:0xee65590c
frame pointer           = 0x28:0xee655924
code segment            = base rx0, limit 0xfffff, type 0x1b
                        = DPL 0, pres 1, def32 1, gran 1
processor eflags        = interrupt enabled, resume, IOPL = 0
current process         = 890 (ng_queue2)
trap number             = 12

(kgdb) backtrace
#0  doadump () at pcpu.h:246
#1  0x8089dd47 in boot (howto=260) at /usr/src/sys/kern/kern_shutdown.c:416
#2  0x8089e039 in panic (fmt=Variable "fmt" is not available.
) at /usr/src/sys/kern/kern_shutdown.c:579
#3  0x80bcfe3c in trap_fatal (frame=0xee67382c, eva=36)
    at /usr/src/sys/i386/i386/trap.c:938
#4  0x80bd00c0 in trap_pfault (frame=0xee67382c, usermode=0, eva=36)
    at /usr/src/sys/i386/i386/trap.c:851
#5  0x80bd0a05 in trap (frame=0xee67382c) at
/usr/src/sys/i386/i386/trap.c:533
#6  0x80bb2adb in calltrap () at /usr/src/sys/i386/i386/exception.s:165
#7  0x8a04c9e4 in ng_path2noderef (here=0x89f85c00,
    address=0x9700d660 "mpd871-B-2-lim:1-0-m", destp=0xee673ac0,
    lasthook=0xee673abc)
    at
/usr/src/sys/modules/netgraph/netgraph/../../../netgraph/ng_base.c:1757
#8  0x8a04cd40 in ng_address_path (here=0x89f85c00, item=0x8a639a40,
    address=0x9700d660 "mpd871-B-2-lim:1-0-m", retaddr=0)
    at
/usr/src/sys/modules/netgraph/netgraph/../../../netgraph/ng_base.c:3522
#9  0x8a0464f2 in ngc_send (so=0x889ed80c, flags=0, m=0x89ce6d00,
    addr=0x94caa1e0, control=0x0, td=0x8889a6f0)
    at
/usr/src/sys/modules/netgraph/socket/../../../netgraph/ng_socket.c:296
#10 0x808ff0d5 in sosend_generic (so=0x889ed80c, addr=0x94caa1e0,
    uio=0xee673be8, top=0x89ce6d00, control=0x0, flags=0, td=0x8889a6f0)
    at /usr/src/sys/kern/uipc_socket.c:1257
#11 0x808fb1ef in sosend (so=0x889ed80c, addr=0x94caa1e0, uio=0xee673be8,
---Type <return> to continue, or q <return> to quit---
    top=0x0, control=0x0, flags=0, td=0x8889a6f0)
    at /usr/src/sys/kern/uipc_socket.c:1301
#12 0x80902ae1 in kern_sendit (td=0x8889a6f0, s=5, mp=0xee673c5c, flags=0,
    control=0x0, segflg=UIO_USERSPACE) at
/usr/src/sys/kern/uipc_syscalls.c:788
#13 0x80902d11 in sendit (td=0x8889a6f0, s=5, mp=0xee673c5c, flags=0)
    at /usr/src/sys/kern/uipc_syscalls.c:724
#14 0x80902e28 in sendto (td=0x8889a6f0, uap=0xee673cf8)
    at /usr/src/sys/kern/uipc_syscalls.c:840
#15 0x80bd03b3 in syscall (frame=0xee673d38)
    at /usr/src/sys/i386/i386/trap.c:1111
#16 0x80bb2b40 in Xint0x80_syscall () at
/usr/src/sys/i386/i386/exception.s:261
#17 0x00000033 in ?? ()

How-To-Repeat: Use mpd and send mpd-limit every 5-10 minutes 2-3 days