linux-next: umh: fix processed error when UMH_WAIT_PROC is used seems to break linux bridge on s390x (bisected)

[Luis Chamberlain]

On Wed, Jun 24, 2020 at 01:17:25PM +0000, Luis Chamberlain wrote:
> I found however an LTP bug indicating the need to test for
> s390 wait macros [0] in light of a recent bug in glibc for s390.
> I am asking for references to that issue given I cannot find
> any mention of this on glibc yet.
> 
> [0] https://github.com/linux-test-project/ltp/issues/605

I looked into this and the bug associated was:

https://sourceware.org/bugzilla/show_bug.cgi?id=19613

The commit in question was upstream glibc commit
b49ab5f4503f36dcbf43f821f817da66b2931fe6 ("Remove union wait [BZ
#19613]"), and while I don't see anything s390 mentioned there,
the issue there was due to the caller of the wait using a long
instead of an int for the return value.

In other words, that'd not the droid we are looking for.

So the issue is something else.

  Luis