RE: [PATCH 0/3] Use mm_struct and switch_mm() instead of manually

From: Prakhya, Sai Praneeth
Date: Tue Dec 19 2017 - 01:24:01 EST

> > Changes in V3:
> > 1. When CPUMASK_OFFSTACK is enabled, switch_mm_irqs_off() sets cpumask
> > by calling cpumask_set_cpu(). This panics kernel as efi_mm is not
> > initialized, therefore initialize efi_mm in efi_alloc_page_tables().
> Thanks for the v3.
> I confirmed that the issue I saw with the v2 when I enabled 'efi=debug' on the
> sgi-uv 300 machine (i.e the NULL pointer access while accessing
> mm_cpumask(next), in the function call
> 'switch_mm_irqs_off') is fixed in the v3.
> Also as I noted during the v2 review, introducing the 'efi_switch_mm() ' helper
> instead of manually twiddling with %cr3 seems more cleaner (having personally
> debugged this leg several times on the underlying x86 EFI machines).
> So in addition to me testing this on the sgi-uv300 and Dell Optiplex EFI enabled
> machine, please feel free to add:
> Reviewed-by: Bhupesh Sharma <bhsharma@xxxxxxxxxx>

Hi Bhupesh,

Thanks for the review and re-iterating the usefulness of this patch set.