Messages in this thread | | | Date | Fri, 15 Dec 2017 17:40:15 +0100 (CET) | From | Thomas Gleixner <> | Subject | Re: general protection fault in show_timer |
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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 <tglx@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
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