Re: [tip:x86/urgent] x86/mm/32: Load a sane CR3 before cpu_init() on secondary CPUs

[Pavel Machek]

On Sun 2017-09-17 11:19:53, tip-bot for Andy Lutomirski wrote:
> Commit-ID:  4ba55e65f471d011d3ba2ac2022180ea0877d68e
> Gitweb:     http://git.kernel.org/tip/4ba55e65f471d011d3ba2ac2022180ea0877d68e
> Author:     Andy Lutomirski <luto@xxxxxxxxxx>
> AuthorDate: Sun, 17 Sep 2017 09:03:51 -0700
> Committer:  Ingo Molnar <mingo@xxxxxxxxxx>
> CommitDate: Sun, 17 Sep 2017 18:59:09 +0200
> 
> x86/mm/32: Load a sane CR3 before cpu_init() on secondary CPUs
> 
> For unknown historical reasons (i.e. Borislav doesn't recall),
> 32-bit kernels invoke cpu_init() on secondary CPUs with
> initial_page_table loaded into CR3.  Then they set
> current->active_mm to &init_mm and call enter_lazy_tlb() before
> fixing CR3.  This means that the x86 TLB code gets invoked while CR3
> is inconsistent, and, with the improved PCID sanity checks I added,
> we warn.
> 
> Fix it by loading swapper_pg_dir (i.e. init_mm.pgd) earlier.
> 
> Reported-by: Paul Menzel <pmenzel@xxxxxxxxxxxxx>
> Reported-by: Pavel Machek <pavel@xxxxxx>

4.14.0-rc1-next-20170919 does not produce the warning during bootup.

									Pavel

Tested-by: Pavel Machek <pavel@xxxxxx>


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