Crash with GRE und IPFW fwd

[Julian Kornberger]

Hi,

I have recurring crashes if I forward GRE packets using IPFW with fwd:
- The first fwd rule forwards incoming traffic into a GRE interface.
- The second fwd rule forwards GRE packets to a gateway.

If there is no GRE traffic, the system is stable. As soon as there is 
GRE traffic i takes araound one to five minutes until is crashes.
If I omit the second fwd rule, it never crashes.

I use a FreeBSD 10.1 on a PC Engines APU.1D board.
Any Ideas how to debug this?

Kind Regards
Julian


Fatal trap 12: page fault while in kernel mode
cpuid = 0; apic id = 00
fault virtual address   = 0x7c
fault code              = supervisor read data, page not present
instruction pointer     = 0x20:0xffffffff80a58105
stack pointer           = 0x28:0xfffffe00957335e0
frame pointer           = 0x28:0xfffffe00957336e0
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         = 1707 (tcpmssd)
trap number             = 12
panic: page fault
cpuid = 0
KDB: stack backtrace:
#0 0xffffffff80963000 at kdb_backtrace+0x60
#1 0xffffffff80928125 at panic+0x155
#2 0xffffffff80d258df at trap_fatal+0x38f
#3 0xffffffff80d25bf8 at trap_pfault+0x308
#4 0xffffffff80d2525a at trap+0x47a
#5 0xffffffff80d0b142 at calltrap+0x8
#6 0xffffffff81a15797 at gre_output+0x467
#7 0xffffffff80a59024 at ip_output+0x11b4
#8 0xffffffff819b257a at div_send+0x33a
#9 0xffffffff8099e0b5 at sosend_generic+0x475
#10 0xffffffff809a4425 at kern_sendit+0x245
#11 0xffffffff809a4749 at sendit+0x129
#12 0xffffffff809a460d at sys_sendto+0x4d
#13 0xffffffff80d26211 at amd64_syscall+0x351
#14 0xffffffff80d0b42b at Xfast_syscall+0xfb