bin/56221: fs/tmpfs/t_vnd crashes ATF on Alpha under Qemu

[thorpej%me.com@localhost]

>Number:         56221
>Category:       bin
>Synopsis:       fs/tmpfs/t_vnd crashes ATF on Alpha under Qemu
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    bin-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sun May 30 20:45:02 +0000 2021
>Originator:     Jason Thorpe
>Release:        NetBSD 9.99.82
>Organization:
RISCy Business
>Environment:
NetBSD alpha-vm 9.99.82 NetBSD 9.99.82 (GENERIC-$Revision: 1.411 $) #72: Sun May 30 08:51:41 PDT 2021  thorpej@the-ripe-vessel:/space/src/sys/arch/alpha/compile/GENERIC.QEMU alpha
>Description:
Running fs/tmpfs/t_vnd on NetBSD/alpha under Qemu results in:

fs/tmpfs/t_vnd (763/889): 1 test cases
    basic: terminate called after throwing an instance of 'tools::system_error'
  what():  tools::fs::cleanup(/tmp/atf-run.EkWRyC/mntpt): unmount(2) failed: Device busy
[2.007647s] Failed: Invalid checksum for file 1
atf-report: ERROR: 143259: Unexpected token `<<EOF>>'; expected end of test
atf-report: program
[1]   Abort trap (core dumped) atf-run |
      Done(1)                 atf-report
alpha-vm# 

I don't know if this happens on real hardware.

>How-To-Repeat:
See above.
>Fix:
N/A