Tests Failures on PPC64

[Oleg Nesterov]

On 12/09, CAI Qian wrote:
>
> ----- "Oleg Nesterov" <oleg at redhat.com> wrote:
>
> > Thanks, but it doesn't fail for me on this machine...
>
> Hmm, it failed for me.
>
> # cd /root/ptrace-tests
>
> # make check
> ...
> FAIL: watchpoint

OMG. Yet another test-case fails on powerpc ???? I didn't see this
failure in the previous reports or missed it ...

I bet it fails without utrace too? (please don't tell it doesn't ;)

Did you see it fails on other ppc64 machines?


Oh well. I spent this day grepping arch/powerpc to understand how
PTRACE_SET_DEBUGREG works and what is the problem. But I am afraid
this time I need a help from someone who understands the hardware
magic on powerpc.

So far:

	- the test-case looks correct to me

	- gdb uses PTRACE_SET_DEBUGREG to implement "watch var" too,
	  and "watch" doesn't work.

	- the tracee notices thread.dabr correctly and calls set_dabr
	  == pseries_set_dabr() from __switch_to

	- but do_dabr() or DebugException() is never called.

Will continue tomorrow...

> # make biarch-check
> ...
> FAIL: ppc-dabr-race

Aaaaah. I didn't notice you did biarch-check, not check.
Will take a look later...

Oleg.