Re: [PATCH 16/18] x86/boot/32: Fix cpu_current_top_of_stack initialization at boot

Borislav Petkov
2017-11-01T10:18:38Z

On Thu, Oct 26, 2017 at 01:26:48AM -0700, Andy Lutomirski wrote:
> cpu_current_top_of_stack's initialization forgot about
> TOP_OF_KERNEL_STACK_PADDING. This bug didn't matter because the
> idle threads never enter user mode.
>
> Signed-off-by: Andy Lutomirski <luto@kernel.org>
> ---
> arch/x86/kernel/smpboot.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
> index ad59edd84de7..06c18fe1c09e 100644
> --- a/arch/x86/kernel/smpboot.c
> +++ b/arch/x86/kernel/smpboot.c
> @@ -961,8 +961,7 @@ void common_cpu_up(unsigned int cpu, struct task_struct *idle)
> #ifdef CONFIG_X86_32
> /* Stack for startup_32 can be just as for start_secondary onwards */
> irq_ctx_init(cpu);
> - per_cpu(cpu_current_top_of_stack, cpu) =
> - (unsigned long)task_stack_page(idle) + THREAD_SIZE;
> + per_cpu(cpu_current_top_of_stack, cpu) = task_top_of_stack(idle);
> #else
> initial_gs = per_cpu_offset(cpu);
> #endif
> --

Reviewed-by: Borislav Petkov <bp@suse.de>

--
Regards/Gruss,
Boris.

SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg)
--