Re: 2.6.25.3: su gets stuck for root

Alan Cox
2008-06-02T08:26:21Z

> Guys, you should test if "kill -CONT $pid" wakes the process up.
> It might be possible that some obscure bug appeared in the tty
> code resulting in SIGTTOU sometimes being sent to the caller,
> although that seems rather strange :-/

Not really. The task would get suspended if it attempted to change the
tty settings while not being session leader. This is part of the POSIX
and BSD job control. A race (either kernel or in something like
sshd/bash) would do that and could have been caused by any of the timing
changes recently.

That would also explain why I can't duplicate it, and the sleep
observation.