Groups > linux.kernel > #1319169

Re: [PATCH] signals: work around random wakeups in sigsuspend()

From	Sasha Levin <sasha.levin@oracle.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH] signals: work around random wakeups in sigsuspend()
Date	2016-01-27 18:30 +0100
Message-ID	<qVC4O-6X5-19@gated-at.bofh.it> (permalink)
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On 01/27/2016 03:44 AM, Peter Zijlstra wrote:
> On Tue, Jan 26, 2016 at 10:10:09PM +0100, Oleg Nesterov wrote:
> 
>> And, ironically, there is another more serious "reverse" problem ;) sigsuspend()
>> orany other user of -ERESTARTNOHAND can "miss" the signal, in a sense that the
>> kernel can wrongly restart this syscall after return from signal handler. This
>> is not trivial to fix..
> 
> So I'm not entirely sure I get what you mean there. But it did get me to
> look at the patch again:
> 
> +       while (!signal_pending(current)) {
> +               __set_current_state(TASK_INTERRUPTIBLE);
> +               schedule();
> +       }
> 
> That should very much be:
> 
> 	for (;;) {
> 		set_current_state(TASK_INTERRUPTIBLE);
> 		if (signal_pending(current))
> 			break;
> 		schedule();
> 	}
> 	__set_current_state(TASK_RUNNING);

Should that be the case for sys_pause() too?


Thanks,
Sasha

Thread

[PATCH] signals: work around random wakeups in sigsuspend() Sasha Levin <sasha.levin@oracle.com> - 2016-01-25 17:00 +0100
  Re: [PATCH] signals: work around random wakeups in sigsuspend() Oleg Nesterov <oleg@redhat.com> - 2016-01-25 20:10 +0100
    Re: [PATCH] signals: work around random wakeups in sigsuspend() Peter Zijlstra <peterz@infradead.org> - 2016-01-25 20:40 +0100
  Re: [PATCH] signals: work around random wakeups in sigsuspend() Andrew Morton <akpm@linux-foundation.org> - 2016-01-25 22:40 +0100
    Re: [PATCH] signals: work around random wakeups in sigsuspend() Oleg Nesterov <oleg@redhat.com> - 2016-01-26 22:20 +0100
      Re: [PATCH] signals: work around random wakeups in sigsuspend() Peter Zijlstra <peterz@infradead.org> - 2016-01-27 09:50 +0100
        Re: [PATCH] signals: work around random wakeups in sigsuspend() Oleg Nesterov <oleg@redhat.com> - 2016-01-27 17:50 +0100
          Re: [PATCH] signals: work around random wakeups in sigsuspend() Peter Zijlstra <peterz@infradead.org> - 2016-01-27 19:00 +0100
          Re: [PATCH] signals: work around random wakeups in sigsuspend() Andrew Morton <akpm@linux-foundation.org> - 2016-01-27 19:40 +0100
            Re: [PATCH] signals: work around random wakeups in sigsuspend() Oleg Nesterov <oleg@redhat.com> - 2016-01-27 22:10 +0100
        Re: [PATCH] signals: work around random wakeups in sigsuspend() Sasha Levin <sasha.levin@oracle.com> - 2016-01-27 18:30 +0100
  Re: [PATCH] signals: work around random wakeups in sigsuspend() Ingo Molnar <mingo@kernel.org> - 2016-01-26 07:50 +0100
    Re: [PATCH] signals: work around random wakeups in sigsuspend() Oleg Nesterov <oleg@redhat.com> - 2016-01-26 16:10 +0100

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