Re: [tip:x86/urgent] x86, apic: Fix apic=debug boot crash

Yinghai Lu
2010-08-20T19:24:24Z

On Fri, Aug 20, 2010 at 5:41 AM, tip-bot for Daniel Kiper
<dkiper@net-space.pl> wrote:
> Commit-ID:  05e407603e527f9d808dd3866d3a17c2ce4dfcc5
> Gitweb:     http://git.kernel.org/tip/05e407603e527f9d808dd3866d3a17c2ce4dfcc5
> Author:     Daniel Kiper <dkiper@net-space.pl>
> AuthorDate: Fri, 20 Aug 2010 00:46:16 +0200
> Committer:  Ingo Molnar <mingo@elte.hu>
> CommitDate: Fri, 20 Aug 2010 10:18:28 +0200
>
> x86, apic: Fix apic=debug boot crash
>
> Fix a boot crash when apic=debug is used and the APIC is
> not properly initialized.
>
> This issue appears during Xen Dom0 kernel boot but the
> fix is generic and the crash could occur on real hardware
> as well.

Do you have any report on real hardware?

that could not happen on real hardware.

Yinghai

>
> Signed-off-by: Daniel Kiper <dkiper@net-space.pl>
> Cc: xen-devel@lists.xensource.com
> Cc: konrad.wilk@oracle.com
> Cc: jeremy@goop.org
> Cc: <stable@kernel.org> # .35.x, .34.x, .33.x, .32.x
> LKML-Reference: <20100819224616.GB9967@router-fw-old.local.net-space.pl>
> Signed-off-by: Ingo Molnar <mingo@elte.hu>
> ---
>  arch/x86/kernel/apic/io_apic.c |    2 ++
>  1 files changed, 2 insertions(+), 0 deletions(-)
>
> diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c
> index 4dc0084..f1efeba 100644
> --- a/arch/x86/kernel/apic/io_apic.c
> +++ b/arch/x86/kernel/apic/io_apic.c
> @@ -1728,6 +1728,8 @@ __apicdebuginit(void) print_IO_APIC(void)
>                struct irq_pin_list *entry;
>
>                cfg = desc->chip_data;
> +               if (!cfg)
> +                       continue;
>                entry = cfg->irq_2_pin;
>                if (!entry)
>                        continue;
> --
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