ifconfig carp1 destroy = kernel panic

[Hugo Silva]

Stefan Lambrev wrote:
> Hi all,
>
> This combination of commands lead my freebsd servers to kernel panic.
>
> ifconfig bge0 192.168.1.1 netmask 255.255.255.0
> ifconfig bge0 alias 10.1.1.1 netmask 255.255.255.0
> ifconfig carp create
> ifconfig carp create
> ifconfig carp0 192.168.1.222/24 vhid 1 advskew 0 pass somekey
> ifconfig carp1 10.1.1.222/24 vhid 2 advskew 0 pass somekey
> - to this point everything is ok -
> ifconfig carp1 destroy - at this point this will cause kernel panic.
> I tested with ifconfig carp1 delete before destroy but the result is 
> the same.
>
> tested on freebsd 6.2 pre-release i386 SMP and freebsd 6.2 release 
> amd64 SMP - in both cases kernel panic.
>
> This seems very similar to this PR - 
> http://www.freebsd.org/cgi/query-pr.cgi?pr=92776
>
> I'm going to test on 6.2 stable from today, but I'm not very optimistic.
>
> Fatal trap 12: page fault while in kernel mode
> cpuid = 0; apic id = 00
> fault virtual address   = 0x24
> fault code              = supervisor read, page not present
> instruction pointer     = 0x20:0xc0555bcd
> stack pointer           = 0x28:0xe4b77bd4
> frame pointer           = 0x28:0xe4b77be8
> code segment            = base 0x0, limit 0xfffff, type 0x1b
>                                 = DPL 0, pres 1, def32 1, gran 1
> processor eflags        = resume, IOPL = 0
> current process         = 14 (swi1: net)
> trap number             = 12
> panic: page fault
> cpuid = 0
> Uptime: 7m2s
> Cannot dump. No dump device defined.
> aac0: shutting down controller...done
>
> P.S. should I open new PR or just follow up to pr #92776 ?
>
Just for the records, I stumbled upon something similar some time ago 
while testing with a co-worker. We both had 6.2-PRERELEASE installed. I 
cannot remember if the same command sequence led to the panic, but we 
were mimicking each other's commands (with the adequate changes for each 
host of course), and both machines panicked on the same command.

Hugo