port-sparc/55316: sparc reports "panic: crazy interrupts" after serial break

[gson%gson.org@localhost (Andreas Gustafsson)]

>Number:         55316
>Category:       port-sparc
>Synopsis:       sparc reports "panic: crazy interrupts" after serial break
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    port-sparc-maintainer
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Fri May 29 15:55:00 +0000 2020
>Originator:     Andreas Gustafsson
>Release:        NetBSD-current, source date 2020.05.17.19.34.07
>Organization:
>Environment:
System: NetBSD
Architecture: sparc
Machine: sparc
>Description:

When I run NetBSD-current/sparc in qemu with a serial console and
send a break sequence by typing "control-a b", I get output like
this:

[  23.8931665] stray interrupt cpu0 ipl 0xc pc=0x31a6c npc=0x31a70 psr=0x4401083<EF,S>
[  23.8931665] stray interrupt cpu0 ipl 0xc pc=0x31a6c npc=0x31a70 psr=0x4401083<EF,S>
[  23.8931665] stray interrupt cpu0 ipl 0xc pc=0x31a6c npc=0x31a70 psr=0x4401083<EF,S>
[  23.8931665] stray interrupt cpu0 ipl 0xc pc=0x31a6c npc=0x31a70 psr=0x4401083<EF,S>
[  23.8931665] stray interrupt cpu0 ipl 0xc pc=0x31a6c npc=0x31a70 psr=0x4401083<EF,S>
[  23.8931665] stray interrupt cpu0 ipl 0xc pc=0x31a6c npc=0x31a70 psr=0x4401083<EF,S>
[  23.8931665] stray interrupt cpu0 ipl 0xc pc=0x31a6c npc=0x31a70 psr=0x4401083<EF,S>
[  23.8931665] stray interrupt cpu0 ipl 0xc pc=0x31a6c npc=0x31a70 psr=0x4401083<EF,S>
[  23.8931665] stray interrupt cpu0 ipl 0xc pc=0x31a6c npc=0x31a70 psr=0x4401083<EF,S>
[  23.8931665] stray interrupt cpu0 ipl 0xc pc=0x31a6c npc=0x31a70 psr=0x4401083<EF,S>
[  23.8931665] stray interrupt cpu0 ipl 0xc pc=0x31a6c npc=0x31a70 psr=0x4401083<EF,S>
[  23.8931665] panic: crazy interrupts
[  23.8931665] cpu0: Begin traceback...
[  23.8931665] 0x0(0xf046c550, 0xf052f2f8, 0xf056bc00, 0xf056cc00, 0x104, 0xf056cae0) at netbsd:panic+0x20
[  23.8931665] panic(0xf046c550, 0x0, 0xc, 0x31a6c, 0x31a70, 0xf052f310) at netbsd:strayintr+0xa4
[  23.8931665] strayintr(0xf052f3b0, 0xf0013b64, 0xf00, 0x48010a3, 0x0, 0x17) at netbsd:sparc_interrupt44c+0x168
[  23.8931665] cpu0: End traceback...
[  23.8931665] Frame pointer is at 0xf052f0b0
[  23.8931665] Call traceback:
[  23.8931665]   pc = 0xf002cc94  args = (0xf056cc7c, 0xf048f8d8, 0xf052f1d0, 0xf04b3400, 0x168, 0xf0548400) fp = 0xf052f120
[  23.8931665]   pc = 0xf02de010  args = (0x104, 0x0, 0xf08b3d00, 0x0, 0x4401fe7, 0xf056a000) fp = 0xf052f188
[  23.8931665]   pc = 0xf031d9b8  args = (0x104, 0x0, 0xf046c550, 0xf052f2f8, 0x0, 0xf0002000) fp = 0xf052f1e8
[  23.8931665]   pc = 0xf031da64  args = (0xf046c550, 0xf052f2f8, 0xf056bc00, 0xf056cc00, 0x104, 0xf056cae0) fp = 0xf052f248
[  23.8931665]   pc = 0xf002a6d0  args = (0xf046c550, 0x0, 0xc, 0x31a6c, 0x31a70, 0xf052f310) fp = 0xf052f2b0
[  23.8931665]   pc = 0xf0008cc0  args = (0xf052f3b0, 0xf0013b64, 0xf00, 0x48010a3, 0x0, 0x17) fp = 0xf052f350
[  23.8931665]   pc = 0x1ec2c  args = (0x1, 0x58, 0x0, 0x0, 0x1c, 0xed964074) fp = 0xeffff6d0

[  23.8931665] dumping to dev 7,1 offset 164063
[  23.8931665] dump succeeded
[  23.8931665] rebooting

I don't know if this is a NetBSD bug or a qemu bug.  I have tried the
following combinations of qemu version and NetBSD version, and they
all panic:

  qemu-5.0.0nb4, -current
  qemu-5.0.0nb4, 7.2
  qemu-3.1.0nb1, -current

>How-To-Repeat:

anita interact http://nycdn.netbsd.org/pub/NetBSD-daily/HEAD/latest/images/NetBSD-9.99.64-sparc.iso
(wait for login prompt)
<control-a> <b>

>Fix: