port-alpha/56197: ATF lib/libc/sys/t_ptrace_wait bytes_transfer_eof_pt_read_d hard hang on Alpha under Qemu

[thorpej%me.com@localhost]

>Number:         56197
>Category:       port-alpha
>Synopsis:       ATF lib/libc/sys/t_ptrace_wait bytes_transfer_eof_pt_read_d hard hang on Alpha under Qemu
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    port-alpha-maintainer
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sat May 22 16:50:00 +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: 1.410 $) #2: Sat May 22 08:06:26 PDT 2021  thorpej@the-ripe-vessel:/space/src/sys/arch/alpha/compile/GENERIC alpha
>Description:
lib/libc/sys/t_ptrace_wait (324/889): 282 test cases
    access_fpregs1: [0.059473s] Passed.
    access_fpregs2: [0.053553s] Passed.
    access_regs1: [0.054060s] Passed.
    access_regs2: [0.054013s] Passed.
    access_regs3: [0.053518s] Passed.
    access_regs4: [0.053677s] Passed.
.
.
.
    bytes_transfer_eof_pt_read_d: <HARD HANG>

Console is unresponsive.

This is under Qemu.  I don't know if it happens on real hardware.


>How-To-Repeat:
See above.  It is 100% reproducible.
>Fix:
N/A