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Groups > linux.kernel > #1606259
| From | Ingo Molnar <mingo@kernel.org> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [lkp-robot] [x86] 69218e4799: BUG:kernel_hang_in_boot_stage |
| Date | 2017-03-22 08:40 +0100 |
| Message-ID | <tnJ2a-7gq-17@gated-at.bofh.it> (permalink) |
| References | (5 earlier) <tnABA-1iQ-7@gated-at.bofh.it> <tnC0G-2r8-11@gated-at.bofh.it> <tnCDn-2El-1@gated-at.bofh.it> <tnGnD-5mA-3@gated-at.bofh.it> <tnGQF-5L3-7@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
* Thomas Garnier <thgarnie@google.com> wrote:
> > static inline void setup_fixmap_gdt(int cpu)
> > {
> > __set_fixmap(get_cpu_gdt_ro_index(cpu),
> > - __pa(get_cpu_gdt_rw(cpu)), pg_fixmap_gdt_flags);
> > + slow_virt_to_phys(get_cpu_gdt_rw(cpu)),
> > + pg_fixmap_gdt_flags);
> > }
> >
> > /* Load the original GDT from the per-cpu structure */
> >
> > This makes UP boot for me, but SMP (2 cpus) is still busted.
>
> This change fixed boot for me:
>
> diff --git a/arch/x86/include/asm/fixmap.h b/arch/x86/include/asm/fixmap.h
> index b65155cc3760..4e30707d9f9a 100644
> --- a/arch/x86/include/asm/fixmap.h
> +++ b/arch/x86/include/asm/fixmap.h
> @@ -104,7 +104,9 @@ enum fixed_addresses {
> FIX_GDT_REMAP_BEGIN,
> FIX_GDT_REMAP_END = FIX_GDT_REMAP_BEGIN + NR_CPUS - 1,
>
> - __end_of_permanent_fixed_addresses,
> + __end_of_permanent_fixed_addresses =
> + (FIX_GDT_REMAP_END + PTRS_PER_PTE - 1) &
> + -PTRS_PER_PTE,
>
> Just ensure PKMAP_BASE & FIX_WP_TEST are on a different PMD.
>
> I don't think that the right fix but it might help understand the
> exact root cause.
Could this be related to the permission bits in the PMD itself getting out of sync
with the PTEs? WP test marks a page writable/unwritable, and maybe we mess up the
restoration. If they are on separate PMDs then this is worked around because the
fixmap GDT is on a separate PMD.
Thanks,
Ingo
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Re: [lkp-robot] [x86] 69218e4799: BUG:kernel_hang_in_boot_stage Thomas Garnier <thgarnie@google.com> - 2017-03-21 19:30 +0100
Re: [lkp-robot] [x86] 69218e4799: BUG:kernel_hang_in_boot_stage Thomas Garnier <thgarnie@google.com> - 2017-03-21 20:30 +0100
Re: [lkp-robot] [x86] 69218e4799: BUG:kernel_hang_in_boot_stage Thomas Garnier <thgarnie@google.com> - 2017-03-21 21:30 +0100
Re: [lkp-robot] [x86] 69218e4799: BUG:kernel_hang_in_boot_stage Linus Torvalds <torvalds@linux-foundation.org> - 2017-03-21 22:20 +0100
Re: [lkp-robot] [x86] 69218e4799: BUG:kernel_hang_in_boot_stage Andy Lutomirski <luto@amacapital.net> - 2017-03-21 23:40 +0100
Re: [lkp-robot] [x86] 69218e4799: BUG:kernel_hang_in_boot_stage Andy Lutomirski <luto@kernel.org> - 2017-03-22 01:10 +0100
Re: [lkp-robot] [x86] 69218e4799: BUG:kernel_hang_in_boot_stage Thomas Garnier <thgarnie@google.com> - 2017-03-22 01:50 +0100
Re: [lkp-robot] [x86] 69218e4799: BUG:kernel_hang_in_boot_stage Andy Lutomirski <luto@kernel.org> - 2017-03-22 05:50 +0100
Re: [lkp-robot] [x86] 69218e4799: BUG:kernel_hang_in_boot_stage Thomas Garnier <thgarnie@google.com> - 2017-03-22 06:20 +0100
Re: [lkp-robot] [x86] 69218e4799: BUG:kernel_hang_in_boot_stage Ingo Molnar <mingo@kernel.org> - 2017-03-22 08:40 +0100
Re: [lkp-robot] [x86] 69218e4799: BUG:kernel_hang_in_boot_stage Andy Lutomirski <luto@amacapital.net> - 2017-03-22 17:40 +0100
Re: [lkp-robot] [x86] 69218e4799: BUG:kernel_hang_in_boot_stage Thomas Garnier <thgarnie@google.com> - 2017-03-22 17:50 +0100
Re: [lkp-robot] [x86] 69218e4799: BUG:kernel_hang_in_boot_stage Andy Lutomirski <luto@kernel.org> - 2017-03-22 18:10 +0100
Re: [lkp-robot] [x86] 69218e4799: BUG:kernel_hang_in_boot_stage Linus Torvalds <torvalds@linux-foundation.org> - 2017-03-21 20:30 +0100
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