Messages in this thread | | | Date | Thu, 21 Jun 2007 22:58:56 +0400 | From | Oleg Nesterov <> | Subject | Re: Fix signalfd interaction with thread-private signals |
| |
On 06/21, Linus Torvalds wrote: > > On Thu, 21 Jun 2007, Oleg Nesterov wrote: > > > > Yes, the target thread is the one that caused the SIGSEGV, it sends the signal > > to itself. entry.S:ret_from_exception should notice this signal and _dequeue_ > > it, no? This signal could be stealed by signal(SIG_IGN) which runs after it > > was delivered. > > Right. But it will dequeue it by *taking* it. > > IOW, this has absolutely nothing to do with signalfd. > > That's all I mean.
Yes.
> > My point was that it is _possible_ to steal a thread-local SIGSEGV even without > > signalfd, nothing bad should happen. > > That makes no sense. > > You don't "steal" it. You take it. It's what SIGSEGV (and _any_ signal) > has always been about. You get the signal, enter the signal handler, and > handle it. > > No "stealing". No signalfd, no *nothing*. Just normal signal behaviour.
_Another_ thread could steal SIGSEGV via read(signalfd) without Ben's patch. This is what Ben and Davide are worried about. I think we should not worry, we have the same situation if this "another" thread does
for (;;) signal(SIGSEGV, SIG_IGN);
do_sigaction() does rm_from_queue_full().
Oleg.
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |