Re: [patch] Re: Problem with exiting threads under NPTL

Roland McGrath
2003-12-15T23:04:55Z

> On Sun, 14 Dec 2003, Ingo Molnar wrote:
> >
> > are you sure this can happen? eligible_child() does this:
>
> Interesting. That code should have been enough, but we've later on added
> extra code into wait_task_zombie to check _exactly_ the same case because
> we saw problems.
>
> Hmm.. Maybe that was to protect against concurrent wait4()'ers (which can
> happen - the wait case only takes the read lock). Threads can wait for
> each others children, after all.

My recollection about the wait_task_* changes was that they were mostly to
address races between concurrent wait4 calls.