linux-kernel - Re: tip/master broken with x2apic and kexec

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Message-ID: <4C3CF650.30905@kernel.org>
Date:	Tue, 13 Jul 2010 16:27:12 -0700
From:	Yinghai Lu <yinghai@...nel.org>
To:	"H. Peter Anvin" <hpa@...or.com>
CC:	Ingo Molnar <mingo@...e.hu>, Thomas Gleixner <tglx@...utronix.de>,
	Suresh Siddha <suresh.b.siddha@...el.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: tip/master broken with x2apic and kexec

On 07/13/2010 03:00 PM, H. Peter Anvin wrote:
> On 07/12/2010 07:59 PM, Yinghai Lu wrote:
>> tip/master: 
>> system1: BIOS enabled x2apic, first kernel boot well, and when kexec second kernel will cause system instant reboot.
>>
>> system2: BIOS not enable x2apic, first kernel boot well and enable x2apic, and kexec second kernel well. but when kexec third kernel will case system instant reboot.
>>
>> linus' tree is ok.
>>
>> but for system2 if boot with nox2apic ,intr-remaping off, iommu off, the kexec loop test will pass.
>>
>> the problem looks start in recent two or three weeks.
>>
>> Any idea?
>>
>> bisecting will take a while, because the system post take a while everytime.
>>
>> Thanks
>>
>> Yinghai Lu
> 
> OK, I found the bug... if you could test out the patch which will be
> sent out shortly I would very much appreciate it.

not sure if your patch is the offending one now.

kL: kernel from linus tree
kT1: kernel from tip
kT2: kernel from tip with reverting your patch

BIOS-->kL ---> kL ---> kL....always working
BIOS-->kT1 ---> kT1 --->  kT1 : between second one and third one system reset instant...
BIOS-->kT2 ---> kT2 --->  kT2 : between second one and third one system reset instant...

BIOS-->kL ---> kL ---> kL ---> then kT1 ---> kT1 .... always working
BIOS-->kL ---> kL ---> kL ---> then kT2 ---> kT2 .... always working

looks like first kernel and second one can not be kernel from tip.

Yinghai
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