Re: general protection fault in perf_misc_flags

From: Borislav Petkov
Date: Wed Sep 30 2020 - 12:31:26 EST


On Wed, Sep 30, 2020 at 06:23:44PM +0200, Dmitry Vyukov wrote:
> Here is the answer:
> https://github.com/google/syzkaller/blob/master/tools/create-gce-image.sh#L189
>
> # rodata=n: mark_rodata_ro becomes very slow with KASAN (lots of PGDs)
>
> I have some vague memory that there was some debug double checking
> that pages are indeed read-only and that debug check was slow, but it
> was always executed without rodata=n.

Sounds like debug_checkwx() which is disabled by turning off
CONFIG_DEBUG_WX.

You could either disable it in your .configs or, provided there's even
such an option, disable KASAN checking around it until that one-time
boot test completes and then reenable KASAN.

--
Regards/Gruss,
Boris.

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