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

From	Al Viro <viro@ZenIV.linux.org.uk>
Newsgroups	linux.kernel
Subject	Re: [PATCH] signals: work around random wakeups in sigsuspend()
Date	2016-02-25 04:20 +0100
Message-ID	<r5UD8-6ag-31@gated-at.bofh.it> (permalink)
References	<qURIG-68y-83@gated-at.bofh.it> <qUUGu-8W-17@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On Mon, Jan 25, 2016 at 08:09:15PM +0100, Oleg Nesterov wrote:
> On 01/25, Sasha Levin wrote:
> >
> > A random wakeup can get us out of sigsuspend() without TIF_SIGPENDING
> > being set.
> 
> and TIF_RESTORE_SIGMASK is just wrong in this case. I'd say this is the
> bugfix, not work-around ;)
> 
> > Avoid that by making sure we were signaled, like sys_pause() does.
> >
> > Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
> 
> Acked-by: Oleg Nesterov <oleg@redhat.com>
> 
> Thanks Sasha.

Out of curiousity - where did that stray wakeup come from?  PTRACE_KILL
used to trigger those, but that got fixed.  How does one trigger that
kind of bugs on the current kernels?

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Re: [PATCH] signals: work around random wakeups in sigsuspend() Al Viro <viro@ZenIV.linux.org.uk> - 2016-02-25 04:20 +0100
  Re: [PATCH] signals: work around random wakeups in sigsuspend() Peter Zijlstra <peterz@infradead.org> - 2016-02-25 09:20 +0100
    Re: [PATCH] signals: work around random wakeups in sigsuspend() Al Viro <viro@ZenIV.linux.org.uk> - 2016-02-25 18:40 +0100

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