Re: Question about tst-stack4

[Adhemerval Zanella <adhemerval dot zanella at linaro dot org>]

On 15/08/2017 18:03, Steve Ellcey wrote:
> I have a question about nptl/tst-stack4.  In the 2.25 release notes,
> this shows up as a failure on a number of platforms.  One references a
> defect report (https://sourceware.org/bugzilla/show_bug.cgi?id=19329)
> and the others all reference a glibc checkin that caused the failure:
> 
> commit 17af5da98cd2c9ec958421ae2108f877e0945451
> Author: Alexandre Oliva <aoliva@redhat.com>
> Date:   Wed Sep 21 22:01:16 2016 -0300
> 
>     [PR19826] fix non-LE TLS in static programs
> 
> 
> In the 2.26 release notes the platforms where it fails all just
> mention a timeout.
> 
> Currently, with top-of-tree sources this test fails for me on
> aarch64 with the new ILP32 ABI but passes with the LP64 ABI.
> The failure I see in nptl/tst-stack4.out is:
> 
> Didn't expect signal from child: got `Segmentation fault'
> 
> Is this the error that the other failing platforms are seeing?
> (ARM, Microblaze, MIPS, Nios II, PowerPC [32 bit soft-float])
> 
> Are there any other platforms that are getting a Segfault?
> Given how often this shows up in other platforms failing list,
> I am not sure if there is a aarch64 ILP32 specific issue here 
> or a more generic bug that has been around for a while.

My understanding is this is a long standing GLIBC issue that
started with BZ#17918 and now is being tracked by BZ#19329
as you indicated.  And since it is a race issue the failure
is not consistent and rely on same factors (load, memory
consistency, etc).  

I have seen this on ppc64le, powerpc32, and on i686 as well 
(on some heavy loaded machine). I also think that this is a not 
a ILP32 specific issue and although I do not recall failing on
AArch64 LP64 I think it can potentially fail there as well.

Szabolcs Nagy may have more information about current issue
status since he was the one trying to fix it.