ucom panic

[Patrick Welche <prlw1%cam.ac.uk@localhost>]

Trying to get the kgdb serial line up to trace the gpio problem, I got the
following panic:

#0  maybe_dump (howto=260) at ../../../../arch/i386/i386/machdep.c:854
854             splx(s);
(gdb) bt
#0  maybe_dump (howto=260) at ../../../../arch/i386/i386/machdep.c:854
#1  0xc03931b4 in cpu_reboot (howto=260, bootstr=0x0)
    at ../../../../arch/i386/i386/machdep.c:875
#2  0xc05387e0 in panic (fmt=0xc071f99d "trap")
    at ../../../../kern/subr_prf.c:302
#3  0xc057f575 in trap (frame=0xce0a4974)
    at ../../../../arch/i386/i386/trap.c:409
#4  0xc010cb0f in calltrap ()
#5  0xc059d477 in ucomstart (tp=0xcd98f8d4) at ../../../../dev/usb/ucom.c:1006
#6  0xc0583848 in ttywait (tp=0xcd98f8d4) at ../../../../kern/tty.c:1428
#7  0xc05838ea in ttywflush (tp=0xcd98f8d4) at ../../../../kern/tty.c:1446
#8  0xc0583c7e in ttylclose (tp=0xcd98f8d4, flag=3)
    at ../../../../kern/tty.c:1573
#9  0xc059c71b in ucomclose (dev=16896, flag=3, mode=8192, l=0xcdc09000)
    at ../../../../dev/usb/ucom.c:592
#10 0xc052c5bf in cdev_close (dev=16896, flag=3, devtype=8192, l=0xcdc09000)
    at ../../../../kern/subr_devsw.c:828
#11 0xc051c689 in spec_close (v=0xce0a4b74)
    at ../../../../miscfs/specfs/spec_vnops.c:1073
#12 0xc05c9427 in ufsspec_close (v=0xce0a4b74)
    at ../../../../ufs/ufs/ufs_vnops.c:1978
#13 0xc064de8a in VOP_CLOSE (vp=0xce1bee6c, fflag=3, cred=0xcda91e40)
    at ../../../../kern/vnode_if.c:274
#14 0xc063f512 in vn_close (vp=0xce1bee6c, flags=3, cred=0xcda91e40)
    at ../../../../kern/vfs_vnops.c:349
#15 0xc064015d in vn_closefile (fp=0xcd872b00)
    at ../../../../kern/vfs_vnops.c:781
#16 0xc0326823 in closef (fp=0xcd872b00) at ../../../../kern/kern_descrip.c:794
#17 0xc0326312 in fd_close (fd=6) at ../../../../kern/kern_descrip.c:679
#18 0xc0542e69 in sys_close (l=0xcdc09000, uap=0xce0a4ce4, retval=0xce0a4d0c)
    at ../../../../kern/sys_descrip.c:463
#19 0xc055122b in sy_call (sy=0xc07545e8, l=0xcdc09000, uap=0xce0a4ce4, 
    rval=0xce0a4d0c) at ../../../../sys/syscallvar.h:61
#20 0xc055109a in syscall (frame=0xce0a4d48)
    at ../../../../arch/x86/x86/syscall.c:151
#21 0xc0100504 in syscall1 ()

(yesterday's -current/i386)

frame 5:
1004            ub = SIMPLEQ_FIRST(&sc->sc_obuff_free);
1005            KASSERT(ub != NULL);

(gdb) print ub
$3 = (struct ucom_buffer *) 0x0
(gdb) print sc->sc_obuff_free
$4 = {sqh_first = 0x0, sqh_last = 0xcd98ff38}

(have dump - kernel is without diagnostic and debug otherwise the gpio prob
wouldn't show(!))

Cheers,

Patrick