Re: Boot crash with 659006b x86/x2apic: Split enable and setup function

From: Laura Abbott
Date: Sun Aug 09 2015 - 10:00:40 EST


(missed the LKML cc apologies for the noise)

On 08/09/2015 06:51 AM, Laura Abbott wrote:
Hi,

We received a report[1] of an early boot crash. The reporter had difficulty getting a full
kernel log to view and only had a screenshot which showed a crash in native_apic_mem_read
(full screenshot available at the bugzilla along with dmesg from working kernel)

Bisection identified the following commit:

commit 659006bf3ae37a08706907ce1a36ddf57c9131d2
Author: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Date: Thu Jan 15 21:22:26 2015 +0000

x86/x2apic: Split enable and setup function

enable_x2apic() is a convoluted unreadable mess because it is used for
both enablement in early boot and for setup in cpu_init().

Split the code into x2apic_enable() for enablement and x2apic_setup()
for setup of (secondary cpus). Make use of the new state tracking to
simplify the logic.

Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Jiang Liu <jiang.liu@xxxxxxxxxxxxxxx>
Cc: Joerg Roedel <joro@xxxxxxxxxx>
Cc: Tony Luck <tony.luck@xxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Link: http://lkml.kernel.org/r/20150115211703.129287153@xxxxxxxxxxxxx
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>

The report indicates that if local x2apic is disabled in the BIOS the kernel boots.

Any ideas?

Thanks,
Laura

[1]https://bugzilla.redhat.com/show_bug.cgi?id=1224764

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