[PATCH v3 2/2] posix: Implement preadv2 and pwritev2

[Florian Weimer]

On 06/02/2017 08:19 PM, Adhemerval Zanella wrote:
> I am even more confident this is indeed a miscompilation from GCC7 branch.
> Using a previous built x86_64-linux-gnu with GCC6 branch I saw no issue, however
> using GCC7 there is indeed the test failure.  And it seems to show only for kernels
> with support for p{read,write}v2 syscall, which means it stress the default
> SYSCALL_CANCEL path.
> 
> However, running a GCC6 built testcase with a GCC7 build glibc (with testrun.sh)
> I saw no issue.  The GCC7 built test also fails with a GCC6 built glibc.  I will
> check with GCC master to see if this is something only on GCC7 branch or if it
> is still on master.
> 
> Also, I seems that for GCC7 only x86_64-linux-gnu is affect on x86.

I see it with GCC 6.3 on Fedora 24, x86-64 as well.  It could be a
broken GCC 7 patch that was backported, or perhaps our constraints for
the syscall instruction are off.

Florian