Re: 6.0BETA3 panic in ip_output (vlan/RIP related?)

On Thu, Sep 01, 2005 at 06:10:35PM +0100, Gavin Atkinson wrote:
> 
> wiggum# reboot
> Sep  1 18:05:05
> wiggum reboot: r
> Faooted by root
> Sep  1 18:05:05 wiggum syslogd: exiting on signal 15
> tal trap 9: general protection fault while in kernel mode
> cpuid = 1; apic id = 01
> instruction pointer     = 0x8:0xffffffff80429420
> stack pointer           = 0x10:0xffffffffb49c4590
> frame pointer           = 0x10:0xffffffffb49c46a0
> 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         = 244 (routed)
> [thread pid 244 tid 100101 ]
> Stopped at      strlen: cmpb    $0,0(%rdi)
> db> tr
> Tracing pid 244 tid 100101 td 0xffffff0061d1b980
> strlen() at strlen
> vsnprintf() at vsnprintf+0x2e
> panic() at panic+0x14b
> _mtx_lock_flags() at _mtx_lock_flags+0xd6
> if_delmulti() at if_delmulti+0x3f
> in_delmulti() at in_delmulti+0x4b
> ip_freemoptions() at ip_freemoptions+0x30
> in_pcbdetach() at in_pcbdetach+0x182
> udp_detach() at udp_detach+0x51
> soclose() at soclose+0x1a0
> soo_close() at soo_close+0x3f
> fdrop_locked() at fdrop_locked+0xa1
> closef() at closef+0x31
> fdfree() at fdfree+0x48a
> exit1() at exit1+0x302
> sys_exit() at sys_exit+0xe
> syscall() at syscall+0x4b2
> Xfast_syscall() at Xfast_syscall+0xa8
> 
> Given I've accidentally been able to panic this machine twice in two
> days, is there any chance a fix or at least a band-aid will be in place
> before the release?

It's a shame, but I can't tell for sure.  The problem in the IP
multicast code is really easy to hit, but it will be rather hard
to fix it without major changes to the code.  The workaround is to
avoid destroying interfaces with multicast groups still joined on
them.  Both panics you saw seemed to result from the code trying
to use memory structures of a now-deceased interface.

-- 
Yar