kern/53230: dwc2 crashes from uaudio

[mlelstv%serpens.de@localhost]

	Note: There was a bad value `seriou' for the field `Severity'.
	It was set to the default value of `serious'.

>Number:         53230
>Category:       kern
>Synopsis:       dwc2 crashes from uaudio
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sun Apr 29 09:35:00 +0000 2018
>Originator:     Michael van Elst
>Release:        NetBSD 8.99.12
>Organization:
-- 
                                Michael van Elst
Internet: mlelstv%serpens.de@localhost
                                "A potential Snark may lurk in every tree."
>Environment:
	
	
System: NetBSD hoppa 8.99.12 NetBSD 8.99.12 (HOPPA) #0: Sun Mar 11 03:42:47 CET 2018 mlelstv@gossam:/home/netbsd-current/obj.evbarm/home/netbsd-current/src/sys/arch/evbarm/compile/HOPPA evbarm
Architecture: earmv6hf
Machine: evbarm
>Description:

Running audiorecord from a uaudio device panics the system with:

lock error: mutex_vector_enter,524: assertion failed: !cpu_intr_p()

db_panic+0x14
vpanic+0x1a4
snprintf
lockdebug_abort+0x70
mutex_abort+0x30
mutex_enter+0x4d8
usb_allocmem_flags+0x54
usb_allocmem+0x1c
dwc2_assign_and_init_hc+0x4cc
dwc2_hcd_select_transactions+0x4b
dwc2_release_channel+0x164
dwc2_hc_xfercomp_intr+0x2b0
dwc2_handle_hcd_intr+0x5a0
dwc2_intr+0xec
pic_dispatch+0x98
pic_do_pending_ints+0x2f0
irq_entry+0x68
idle_loop+0x170

Apparently the dwc2 code tries to allocate an alignment buffer from within
an interrupt handler.


>How-To-Repeat:

Use dwc2 with recording from uaudio.

>Fix:
	

>Unformatted: