Re: [tip:perf/core] x86, 64-bit: Fix copy_[to/from]_user() checksfor the userspace address limit

From: Ingo Molnar
Date: Wed May 18 2011 - 17:00:16 EST

* Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:

> On Wed, May 18, 2011 at 1:43 PM, tip-bot for Jiri Olsa <jolsa@xxxxxxxxxx> wrote:
> > As reported in BZ #30352:
> >
> >
> >
> > there's a kernel bug related to reading the last allowed page on x86_64.
> Btw, I think this message is very misleading.
> It has nothing what-so-ever to do with "the last allowed page".

Yeah, i noticed that and this is why i added this bit from Brian's explanation
to the end of the commit:

The bug is that the last byte before the guard page can't be read
because of the off-by-one error. The guard page is left in place.

I should have fixed the original changelog instead of trying to clarify it via
appending it ...


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