On Thu, 14 Dec 2017, Eric Biggers wrote:
> On Thu, Dec 14, 2017 at 04:34:12PM +0100, Thomas Gleixner wrote:
> > On Thu, 14 Dec 2017, Dmitry Vyukov wrote:
> > > On Thu, Dec 14, 2017 at 3:26 PM, Thomas Gleixner <t...@linutronix.de>
> > > wrote:
> > > > On Tue, 12 Dec 2017, Greg KH wrote:
> > > >> Did this ever go anywhere? I don't see it in Linus's tree yet...
> > > >
> > > > I learned yesterday that syzboz is understuffed and cannot test
> > > > patches, so
> > > > I need to find a minute to run the reproducer myself and verify that the
> > > > patch is correct.
> > >
> > > Hi Thomas,
> > >
> > > Why do you say so? Have you tried to ask it to test?
> > > https://github.com/google/syzkaller/blob/master/docs/syzbot.md#communication-with-syzbot
> > > What happened?
> >
> > Eric explained that to me yesterday and I did not try yet.
> >
>
> Your patch definitely fixes the bug (I tested the C reproducers, you just need
> to build a kernel with CONFIG_CHECKPOINT_RESTORE=y and CONFIG_POSIX_TIMERS=y,
> then run them). The real question is whether the check being introduced is
> too
> strict -- are there users passing in other values for ->sigev_notify that
> would
> be broken? That I can't really answer.
Me neither. The manpage is rather clear about the possible values, so I
don't expect wreckage. Aside of that non canonical values would have to
have bit 2, i.e. SIGEV_THREAD_ID cleared because that already has a
restriction that it's only allowed with SIGEV_SIGNAL. So unlikely...
If really some crap application breaks we can handle it in the default
clause by setting it to SIGEV_SIGNAL. Though I rather prefer not to do that
unless it turns out to be absolutely necessary.
Thanks,
tglx
