Messages in this thread | | | Date | Tue, 17 Mar 2009 10:25:46 +0100 | From | Oleg Nesterov <> | Subject | Re: Q: SEGSEGV && uc_mcontext->ip (Was: Signal delivery order) |
| |
On 03/17, Gábor Melis wrote: > > On Martes 17 Marzo 2009, Oleg Nesterov wrote: > > > > But this doesn't look very nice. So, perhaps we can do another > > change? > > > > --- arch/x86/mm/fault.c > > +++ arch/x86/mm/fault.c > > @@ -177,6 +177,13 @@ static void force_sig_info_fault(int si_ > > { > > siginfo_t info; > > > > + current->saved_sigmask = current->blocked; > > + spin_lock_irq(¤t->sighand->siglock); > > + siginitsetinv(¤t->blocked, sigmask(si_signo) | > > + sigmask(SIGKILL) | sigmask(SIGSTOP)); > > + spin_unlock_irq(¤t->sighand->siglock); > > + set_restore_sigmask(); > > + > > info.si_signo = si_signo; > > info.si_errno = 0; > > info.si_code = si_code; > > > > But this is a user-visible change, all signals will be blocked until > > sigsegv_handler() returns. But with this change sigsegv_handler() > > always has the "correct" rt_sigframe. > > As an application developer what I'd like to have is this: synchronously > generated signals are delivered before asynchronously generated ones. > That is, if a number of signals are generated but not yet delivered > then the synchronously generated ones are delivered first. I guess, in > the kernel this would mean that the private/non-private distinction is > not enough.
With the change like above, no other signal (except SIGKILL) can be delivered until the signal handler returns.
Probably it is better to just change force_sig_info(), in this case SIGFPE/etc will have the same behaviour.
> The only thing that > worries me is this remark from Oleg > (http://marc.info/?l=linux-kernel&m=123711058421913&w=2): > > "But please note that it is still possible to hit is_signal_blocked() > even with test_with_kill(), but the probability is very low."
Sorry for confusion. Initially I misread test_with_kill() case, and then forgot to remove this part. I think this is not possible.
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/
| |