Re: [PATCH/RFC] signal races/bugs, losing TIF_SIGPENDING and otherwoes

From: Davide Libenzi
Date: Tue Jun 05 2007 - 20:37:48 EST


On Tue, 5 Jun 2007, Nicholas Miell wrote:

> On Tue, 2007-06-05 at 17:11 -0700, Davide Libenzi wrote:
> > On Tue, 5 Jun 2007, Nicholas Miell wrote:
> >
> > > Yes, that's certainly wrong, but that's an implementation issue. I was
> > > more concerned about the design of the API.
> > >
> > > Naively, I would expect a reads on a signalfd to return either process
> > > signals or thread signals targeted towards the thread doing the read.
> > >
> > > What it actually does (delivering process signals or thread signals
> > > targeted towards the thread that created the signalfd) is weird.
> > >
> > > For one, it means you can't create a single signalfd, stick it in an
> > > epoll set, and then wait on that set from multiple threads.
> >
> > In your box threads do share the sighand, don't they? :)
> >
>
> I have no idea what you're trying to say, but it doesn't appear to
> address the issue I raise.

"For one, it means you can't create a single signalfd, stick it in an
epoll set, and then wait on that set from multiple threads."

Why not?
A signalfd, like I said, is attached to the sighand, that is shared by the
threads.



- Davide


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