On Wed, 20 Dec 2017, Thomas Gleixner wrote:
> From: Vlastimil Babka <[email protected]>
>
> CONFIG_PAGE_TABLE_ISOLATION is relatively new and intrusive feature that may
> still have some corner cases which could take some time to manifest and be
> fixed. It would be useful to have Oops messages indicate whether it was
> enabled for building the kernel, and whether it was disabled during boot.
>
> Example of fully enabled:
>
> Oops: 0001 [#1] SMP PTI
>
> Example of enabled during build, but disabled during boot:
>
> Oops: 0001 [#1] SMP NOPTI
>
> We can decide to remove this after the feature has been tested in the field
> long enough.
>
> [ tglx: Made it use boot_cpu_has() as requested by Borislav ]
>
> Signed-off-by: Vlastimil Babka <[email protected]>
> Signed-off-by: Thomas Gleixner <[email protected]>
> Reviewed-by: Eduardo Valentin <[email protected]>
> Acked-by: Dave Hansen <[email protected]>
FWIW
Acked-by: Jiri Kosina <[email protected]>
I've had a much more stupid variant of this when fuzzing pti/nopti kernels
(distro backports, of course), and it was really helpful when diving into
the crashes.
Thanks,
--
Jiri Kosina
SUSE Labs
