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Groups > linux.kernel > #1527874
| From | Peter Zijlstra <peterz@infradead.org> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [RFC][PATCH] x86: Verify access_ok() context |
| Date | 2016-11-22 20:40 +0100 |
| Message-ID | <sGp58-32O-49@gated-at.bofh.it> (permalink) |
| References | <sGg1Q-5rf-29@gated-at.bofh.it> <sGn3j-1LJ-11@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On Tue, Nov 22, 2016 at 09:28:01AM -0800, Andy Lutomirski wrote:
> On Tue, Nov 22, 2016 at 1:57 AM, Peter Zijlstra <peterz@infradead.org> wrote:
> > +#define access_ok(type, addr, size) \
> > +({ \
> > + WARN_ON_ONCE(!in_task()); \
>
> Should this be guarded by some debug option? This may hurt
> performance on production systems quite a bit.
I suspected something like that; any suitable CONFIG come to mind? I'm
somewhat reluctant to create yet another one for this.
CONFIG_DEBUG_VM seems somehow inappropriate.
> For what it's worth, I think ARM recently started saving the address
> limit and resetting it to USER_DS on NMI entry.
Up to them of course, but doing less on interrupt entry/exit seems
better.
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[RFC][PATCH] x86: Verify access_ok() context Peter Zijlstra <peterz@infradead.org> - 2016-11-22 11:00 +0100
Re: [RFC][PATCH] x86: Verify access_ok() context Andy Lutomirski <luto@amacapital.net> - 2016-11-22 18:30 +0100
Re: [RFC][PATCH] x86: Verify access_ok() context Peter Zijlstra <peterz@infradead.org> - 2016-11-22 20:40 +0100
Re: [RFC][PATCH] x86: Verify access_ok() context Linus Torvalds <torvalds@linux-foundation.org> - 2016-11-22 20:50 +0100
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