Re: ATF X86 race with Debug Registers

[Andreas Gustafsson <gson%gson.org@localhost>]

Kamil Rytarowski wrote:
> Sometimes we catch a bug with Debug Registers in the ptrace(2) tests:
> 
> NetBSD/amd64
> http://releng.netbsd.org/b5reports/amd64/2018/2018.03.06.11.21.31/test.html#lib_libc_sys_t_ptrace_wait6_dbregs_dr3_trap_variable_readwrite_write_2bytes
> 
> NetBSD/i386
> http://releng.netbsd.org/b5reports/i386/2017/2017.12.06.17.54.58/test.html#lib_libc_sys_t_ptrace_wait3_dbregs_dr2_trap_variable_readwrite_read_2bytes
> 
> I was trying to reproduce this locally on a real hardware and in qemu
> (softemu), including concurrent execution, but after merely 100M
> attempts to reproduce the test-case, I've not encountered a single failure.
> 
> Are there some special properties of these releng machines? qemu+kvm?

Nothing special about it AFAIK, it's just qemu from pkgsrc running on
babylon5.netbsd.org, a dual Xeon L5630, under NetBSD 7.1_STABLE.
Typical load is 6-8 qemu processes and a niced -j 16 build.  There's
no kvm - that's only supported under Linux.

If you look at the test.log file corresponding to the test.html, you
can find the qemu version and full qemu command line near the top.
-- 
Andreas Gustafsson, gson%gson.org@localhost