Re: BETA4 kernel panic on boot with USB devices

On Tue, Sep 14, 2004 at 07:00:59PM +0900, FUJIMOTO Kou wrote:
> Hi,
> 
> I found 5.3-BETA4 kernel hangs on boot sequence.
[snip]
> after this message, kernel panic occurs.

I've seen this, too. (though I'm using 6.0-CURRENT of today.)
odin:~ $ uname -a
FreeBSD odin 6.0-CURRENT FreeBSD 6.0-CURRENT #1: Fri Sep 17 13:32:39 KST 2004     root_at_odin:/usr/obj/usr/src/sys/ODIN  i386
odin:~ $ 


I'm using usb keyboard with 2-port usb hub.
(HHK lite2, maybe same as FUJIMOTO-san's. ;-))


The following is the tr output in the DDB. (hand-writen)

instruction ptr. 0x8:0xc04c6b73
kobj_delete()
device_delete_child()
usb_disconnect_port()
uhub_detach()
device_detach()
device_delete_child()
usb_disconnect_port()
uhub_explore()
usb_discover()
usb_event_thread()
fork_exit()
fork_trampoline()


Grepped output of instruction pointer.

odin:/usr/obj/usr/src/sys/ODIN $ nm kernel.debug | grep c04c6b
c04c6b68 T kobj_delete
odin:/usr/obj/usr/src/sys/ODIN $


kgdb output.

(kgdb) l *0xc04c6b73
0xc04c6b73 is in kobj_delete (/usr/src/sys/kern/subr_kobj.c:323).
318     }
319
320     void
321     kobj_delete(kobj_t obj, struct malloc_type *mtype)
322     {
323             kobj_class_t cls = obj->ops->cls;
324             int refs;
325
326             /*
327              * Consider freeing the compiled method table for the class
(kgdb) fr 24
#24 0xc04c23dc in device_delete_child (dev=0x0, child=0xc1ffba00)
    at /usr/src/sys/kern/subr_bus.c:1489
1489            kobj_delete((kobj_t) child, M_BUS);
(kgdb) p *child
$3 = {ops = 0x0, link = {tqe_next = 0x0, tqe_prev = 0xc1ffbd98}, devlink = {
    tqe_next = 0x0, tqe_prev = 0xc1ffbd8c}, parent = 0xc1ffbd80, children = {
    tqh_first = 0x0, tqh_last = 0xc1ffba18}, driver = 0x0, devclass = 0x0, 
  unit = -1, nameunit = 0x0, desc = 0x0, busy = 0, state = DS_NOTPRESENT, 
  devflags = 0, flags = 53, order = 0 '\0', pad = 0 '\0', ivars = 0xc1d2fdc0, 
  softc = 0x0, sysctl_ctx = {tqh_first = 0xc1a40870, tqh_last = 0xc1a72784}, 
  sysctl_tree = 0x0}


This panic is 100% reproducible if I unplug the keyboard.
Or, boot with the keyboard plugged. (As FUJIMOTO-san said,
USB keyboard and mouse are detached and reattached in boot sequence.)

Regards,
Sangwoo