kern/50185: dwctwo attach failure

[martin%NetBSD.org@localhost]

>Number:         50185
>Category:       kern
>Synopsis:       dwctwo attach failure
>Confidential:   no
>Severity:       critical
>Priority:       high
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Mon Aug 31 20:40:00 +0000 2015
>Originator:     Martin Husemann
>Release:        NetBSD 7.99.21
>Organization:
The NetBSD Foundation, Inc.
>Environment:

ERLITE evbmips64

>Description:

After recent dwctwo update, ERLITE does not boot any more:

dwctwo0 at iobus0 address 0x0001180068000000
panic: kernel diagnostic assertion "xc_tailp < xc->xc_headp" failed: file "../../../../kern/subr_xcall.c", line 280 
kernel: breakpoint trap
Stopped in pid 0.1 (system) at  netbsd:cpu_Debugger+0x4:        jr      ra
                bdslot: nop
db> bt
0x90000000000bea80: cpu_Debugger+4 (63061,9001180000000800,6,ffffffff805329f0) r
a ffffffff8039dcac sz 0
0x90000000000bea80: vpanic+15c (63061,9001180000000800,6,ffffffff805329f0) ra ff
ffffff80475dc8 sz 64
0x90000000000beac0: kern_assert+48 (63061,ffffffff80493880,ffffffff804b6520,ffff
ffff804b6470) ra ffffffff803a487c sz 96
0x90000000000beb20: xc_broadcast+25c (63061,ffffffff80493880,ffffffff804b6520,ff
ffffff804b6470) ra ffffffff802d392c sz 80
0x90000000000beb70: softint_disestablish+84 (63061,ffffffff80493880,ffffffff804b
6520,ffffffff804b6470) ra ffffffff80222184 sz 80
0x90000000000bebc0: dwc2_init+18c (63061,ffffffff80493880,ffffffff804b6520,fffff
fff804b6470) ra ffffffff8034cf38 sz 160
0x90000000000bec60: octeon_dwc2_attach+938 (63061,ffffffff80493880,ffffffff804b6
520,ffffffff804b6470) ra ffffffff8038474c sz 32
0x90000000000bec80: config_attach_loc+1b4 (63061,ffffffff80493880,ffffffff804b65
20,ffffffff804b6470) ra ffffffff80351c44 sz 64
0x90000000000becc0: iobus_attach+174 (63061,ffffffff80493880,ffffffff804b6520,ff
ffffff804b6470) ra ffffffff8038474c sz 144
0x90000000000bed50: config_attach_loc+1b4 (63061,ffffffff80493880,ffffffff804b65
20,ffffffff804b6470) ra ffffffff802e81b8 sz 64
0x90000000000bed90: mainbus_attach+a0 (63061,ffffffff80493880,ffffffff804b6520,f
fffffff804b6470) ra ffffffff8038474c sz 80

>How-To-Repeat:
Try to boot evbmips64 on ERLITE

>Fix:
n/a