Re: [PATCH 5.14 298/334] time: Handle negative seconds correctly in timespec64_to_ns()

[Greg Kroah-Hartman]

On Fri, Sep 17, 2021 at 09:31:33AM +0200, Arnd Bergmann wrote:
> On Fri, Sep 17, 2021 at 12:32 AM Thomas Gleixner <tglx@xxxxxxxxxxxxx> wrote:
> > On Wed, Sep 15 2021 at 21:00, Arnd Bergmann wrote:
> >
> > I have done the analysis. setitimer() does not have any problem with
> > that simply because it already checks at the call site that the seconds
> > value is > 0 and so do all the other user visible interfaces. See
> > get_itimerval() ...
> 
> Right, I now came to the same conclusion after taking a closer look,
> see my reply from yesterday.
> 
> > Granted  that the kernel internal interfaces do not have those checks,
> > but they already have other safety nets in place to prevent this and I
> > could not identify any callsite which has trouble with that change.
> >
> > If I failed to spot one then what the heck is the problem? It was broken
> > before that change already!
> 
> My bad for the unfortunate timing. When only saw the patch when Greg
> posted it during the stable review and wasn't completely sure about it
> at the time, so I was hoping that he could just hold off until you had a chance
> to reply either saying that you had already checked this case or that it
> was dangerous, but now it's already reverted.
> 
> I agree we should put back the fix into all stable kernels.

Ok, I'll queue it up again after this round goes out.

thanks for the additional review.

greg k-h