Near-term pf plans

[Niels]

> On 24 Aug 2015, at 18:16, Kristof Provost <kp at FreeBSD.org> wrote:
> 
>>> - PR 202351
>>> This is a panic after ip6 reassembly in pf. We set the rcvif to NULL
>>> when refragmenting. That seems to go OK execpt when we're refragmenting
>>> broadcast/multicast packets in the forwarding path. It's not at all
>>> clear to me how that could happen.
>> 
>> if_bridge wants to forward ipv6 multicasts. pf refragmentation code tries to send out the resulting packets using ip6_forward() which does not handle multicasts, drops the packet and tries to log that fact, which causes the panic.
>> 
>> I’ve updated the PR with some more thoughts about this.
>> 
> Yes, I saw that pass by earlier. Thanks for that, I think you did a great analysis.
> 
> Unfortunately there are other issues with pf on bridges. (See PR 185633 for example)
> I wouldn’t expect the fragmentation and reassembly to work at all in that scenario.
> 
> I’ll see what I can do about at least fixing the panic in the short term.
> Even if the reassembly/refragmentation doesn’t work (on bridges) we should at least no panic.
> 
> Regards,
> Kristof

Is this just the very same issue I see after upgrading to i386 releng/10.2 on my pf/bridge/ip6 router?

It has a bunch of interfaces bridged on the lan, and an mpd/ng interface with IP6 default route over it. Right after booting it crashes with

Fatal trap 12: page fault while in kernel mode
cpuid = 0; apic id = 00
fault virtual address	= 0x14
fault code		= supervisor read, page not present
instruction pointer	= 0x20:0xc0c0175d
stack pointer	        = 0x28:0xf279346c
frame pointer	        = 0x28:0xf2793474
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		= 12 (irq268: em3:rx0)
trap number		= 12
panic: page fault
cpuid = 0
KDB: stack backtrace:
#0 0xc0b805e2 at kdb_backtrace+0x52
#1 0xc0b417bb at vpanic+0x11b
#2 0xc0b4169b at panic+0x1b
#3 0xc1097ceb at trap_fatal+0x30b
#4 0xc1098055 at trap_pfault+0x355
#5 0xc1097724 at trap+0x674
#6 0xc1082a6c at calltrap+0x6
#7 0xc0b8524e at kvprintf+0x81e
#8 0xc0b85fab at _vprintf+0x7b
#9 0xc0b846d8 at log+0x38
#10 0xc0d37626 at ip6_forward+0x236
#11 0xc1aab8ee at pf_refragment6+0x18e
#12 0xc1a9bba9 at pf_test6+0x1609
#13 0xc1aa4e8f at pf_check6_out+0x5f
#14 0xc0c1b942 at pfil_run_hooks+0x82
#15 0xc1ac8219 at bridge_pfil+0x279
#16 0xc1ac92f6 at bridge_broadcast+0xc6
#17 0xc1ac912d at bridge_forward+0x21d
Uptime: 2m56s

Regards,

Niels