kern/147769: 'ifconfig epair0 create' hangs the whole system

[Michael Moll]

>Number:         147769
>Category:       kern
>Synopsis:       'ifconfig epair0 create' hangs the whole system
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Thu Jun 10 17:50:00 UTC 2010
>Closed-Date:
>Last-Modified:
>Originator:     Michael Moll
>Release:        9.0-CURRENT
>Organization:
>Environment:
FreeBSD fujisan.kvedulv.de 9.0-CURRENT FreeBSD 9.0-CURRENT #0: Thu Jun 10 18:09:12 CEST 2010     root at fujisan.kvedulv.de:/usr/obj/usr/src/sys/VIMAGE  sparc64
>Description:
This might be specific to sparc64 - or a general VImage problem.

I use r208975 and the following kernel config:
<snip>
include GENERIC
ident VIMAGE
nooptions SCTP
options VIMAGE
options BREAK_TO_DEBUGGER
</snip>

When doing a 'ifconfig epair0 create' the whole machine hangs (no I/O, no ping). A backtrace after breaking shows:

db> bt
Tracing pid 2135 tid 100124 td 0xfffff800045f9270
uart_intr() at uart_intr+0x1ac
intr_event_handle() at intr_event_handle+0x5c
intr_execute_handlers() at intr_execute_handlers+0x8
intr_fast() at intr_fast+0x68
-- interrupt level=0xc pil=0 %o7=0xc0088ff8 --
-- fast data access mmu miss tar=0x127d2a000 %o7=0xc03d7d40 --
mtx_init() at mtx_init+0x134
epair_modevent() at epair_modevent+0xe4
module_register_init() at module_register_init+0xdc
linker_load_module() at linker_load_module+0xbd8
kern_kldload() at kern_kldload+0xd0
kldload() at kldload+0x60
syscallenter() at syscallenter+0x268
syscall() at syscall+0x74
-- syscall (304, FreeBSD ELF64, kldload) %o7=0x102fe0 --
userland() at 0x408c2028
user trace: trap %o7=0x102fe0
pc 0x408c2028, sp 0x7fdffffd8e1
pc 0x104504, sp 0x7fdffffda11
pc 0x102510, sp 0x7fdffffe291
pc 0x40226f54, sp 0x7fdffffe351
done

>How-To-Repeat:

>Fix:


>Release-Note:
>Audit-Trail:
>Unformatted: