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

From: Peter Zijlstra
Date: Wed Jan 27 2016 - 03:44:52 EST

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 (;;) {
if (signal_pending(current))