FAIL nptl/tst-robustpi4

[Torvald Riegel]

On Thu, 2017-01-26 at 11:12 -0500, Carlos O'Donell wrote:
> On 01/26/2017 10:29 AM, Stefan Liebler wrote:
> > It seems as a race between futex- and exit-syscall causes ESRCH
> > result from futex-syscall.

I'll have a closer look at this.

> > I see those fails with Linux 4.8 / 4.9 running in a z/VM guest as
> > well as with 4.6 on a LPAR (but less often).
> 
> I've seen tst-robustpi7 and tst-robustpi8 failures on all hardware
> across a wide number of kernels, but never tst-robustpi4.
> 
> https://sourceware.org/bugzilla/show_bug.cgi?id=19004
> 
> The robustpi support is certainly not very robust as Torvald's
> recent fixes show, and there still remains at least one design
> flaw that can't be fixed.
> 
> e.g.
> https://sourceware.org/bugzilla/show_bug.cgi?id=14485

The underlying problem for that bug does not affect PI+robust, just
robust, I think.  Unless I forgot about something, PI+robust should
always use the kernel to unlock.