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

[Christoph Hellwig]

On Wed, Jun 24, 2020 at 01:11:54PM +0200, Christian Borntraeger wrote:
> Does anyone have an idea why "umh: fix processed error when UMH_WAIT_PROC is used" breaks the
> linux-bridge on s390?

Are we even sure this is s390 specific and doesn't happen on other
architectures with the same bridge setup?