Messages in this thread | | | Date | Fri, 2 Jul 2004 09:15:12 +0200 | From | Ingo Molnar <> | Subject | Re: Do x86 NX and AMD prefetch check cause page fault infinite loop? |
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* Jamie Lokier <jamie@shareable.org> wrote:
> > - if (pmd_val(*pmd) & _PAGE_NX) > > - printk(KERN_CRIT "kernel tried to access NX-protected page - exploit attempt? (uid: %d)\n", current->uid); > > - } > > - } > > -#endif > > + if (nx_enabled && (error_code & 16)) > > + printk(KERN_CRIT "kernel tried to execute NX-protected page - exploit attempt? (uid: %d)\n", current->uid); > > According to AMD's manual, bit 4 of error_code means the fault was due > to an instruction fetch. It doesn't imply that it's an NX-protected > page: it might be a page not present fault instead. (The manual > doesn't spell that out, it just says the bit is set when it's an > instruction fetch).
you are right, it doesnt say it's an NX related fault.
I'll test this out and send a delta patch.
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