Re: Fix signalfd interaction with thread-private signals

Oleg Nesterov
2007-06-19T20:08:16Z

On 06/19, Davide Libenzi wrote:
>
> On Tue, 19 Jun 2007, Oleg Nesterov wrote:
>
> > On 06/19, Benjamin Herrenschmidt wrote:
> > >
> > > On Tue, 2007-06-19 at 13:14 +0400, Oleg Nesterov wrote:
> > >
> > > > The commited "Fix signalfd interaction with thread-private signals"
> > > > (commit caec4e8dc85e0644ec24aeb36285e1ba02da58cc) doesn't implement
> > > > this.
> > >
> > > Indeed, if you want what Davide described, you need to also change
> > > signalfd side. The patch I did merely prevents another thread from
> > > dequeuing somebody else private signals.
> >
> > Yes I see, but why do we need this change? Yes, we can dequeue SIGSEGV
> > from another thread. Just don't do it if you have a handler for SIGSEGV?
>
> I believe it can be confusing to have private signals dequeued from
> another thread. The kernel expect those to be dequeued by the target
> thread.

Well, I think the kernel doesn't make any assumptions on that. It can't
guarantee the signal will be actually dequeued, to begin with.

(That said, I probably missed something, in that case I'd like to be
educated. This is the real reason why I am making the noise :)

Oleg.