kern/56073: pad(4) panics in audio(4) in -current

[nia%pkgsrc.org@localhost]

>Number:         56073
>Category:       kern
>Synopsis:       pad(4) panics in audio(4) in -current
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Wed Mar 24 13:30:00 +0000 2021
>Originator:     nia
>Release:        9.99.81
>Organization:
>Environment:
NetBSD r 9.99.81 NetBSD 9.99.81 (NIAAMD64) #39: Thu Mar 18 14:53:04 CET 2021  nia@r:/home/nia/cvs/src/sys/arch/amd64/compile/obj/NIAAMD64 amd64
>Description:
As well as no longer returning 0's when its respective audio device is inactive, I now see panics with pad(4) in current.

[ 59773.497851] panic: kernel diagnostic assertion "sc->sc_ropens > 0" failed: file "/home/nia/cvs/src/sys/dev/audio/audio.c", line 2622
>How-To-Repeat:
use pad(4).
>Fix: