* Re: [Fastboot] kexec - 2.6.14 - loads BIOS again
2009-09-29 0:41 ` Eric W. Biederman
@ 2009-09-29 2:48 ` Prabhakar K.
2009-09-30 19:03 ` Prabhakar K.
2009-10-01 0:07 ` Prabhakar K.
2 siblings, 0 replies; 9+ messages in thread
From: Prabhakar K. @ 2009-09-29 2:48 UTC (permalink / raw)
To: Eric W. Biederman; +Cc: fastboot, Kexec Mailing List
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From: Eric W. Biederman <ebiederm@xmission.com>
Subject: Re: [Fastboot] kexec - 2.6.14 - loads BIOS again
To: "Prabhakar K." <krishkar99@yahoo.com>
Cc: "Kexec Mailing List" <kexec@lists.infradead.org>, fastboot@lists.linux-foundation.org
Date: Tuesday, September 29, 2009, 6:11 AM
"Prabhakar K." <krishkar99@yahoo.com> writes:
>> Hi - After my previous posting I was able to make some progress.
>>
>> When I do
>>
>> kexec -l vmlinux --append="init 1 root=/dev/hda2" --console-serial
>>
>> and
>> kexec -e,
>>
>> I get message:
>>
>> Starting new kernel
>> I'm in purgatory
>>
>> And after that it still boots from BIOS (to the same first kernel).
>>
>> Whats the problem here?
>
> I would recommend instrumenting up purgatory and then your target kernel.
>
> It is quite possible the problem is in your backport.
>
>>>>>
> I have instrumented the purgatory code. when I run kexec -e, It hangs for a
> while at
> sha256_starts(&ctx); in the function verify_sha256_digest(), and then reboots
> to the first kernel (from BIOS). I have put debug prints in sha256_starts, but
> none of those are executed.
>
> Interestingly, the same function sha256_starts is executed during kexec -l,
> which is called as part of update_purgatory( )( when my_load( ) is called from
> kexec.c).
> so its surprise why the same function is giving problems when kexec -e is run.
Do you by any chance have a watchdog you are not petting?
>> Yes, we do have software watchdog and hardware watchdog. I disabled software watchdog and I think the reason for resetting to the first kernel can be explained due to hardware watchdog kicking in.
To try out a different version of the kexec, I took kexec version 20080227 from http://www.kernel.org/pub/linux/kernel/people/horms/kexec-tools/and instrumented that code as well. With this, I was able to see the sha 256 verification done during kexec -e and also the post verification of purgatory code. And it hangs there (does not reboot to the first kernel).
So, any conclusions based on these ? Please CC me in reply. Thanks !!
Eric
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^ permalink raw reply [flat|nested] 9+ messages in thread* Re: [Fastboot] kexec - 2.6.14 - loads BIOS again
2009-09-29 0:41 ` Eric W. Biederman
2009-09-29 2:48 ` Prabhakar K.
@ 2009-09-30 19:03 ` Prabhakar K.
2009-10-01 0:07 ` Prabhakar K.
2 siblings, 0 replies; 9+ messages in thread
From: Prabhakar K. @ 2009-09-30 19:03 UTC (permalink / raw)
To: Eric W. Biederman; +Cc: fastboot, Kexec Mailing List
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I have back ported to multiple versions of different kexec-tools. Also I disabled watchdogs so that the first kernel reboot is not kicked in.Now, with all those kexec-tools I see that it hangs after post_verification_setup_arch( ).And I had to hard reboot the router box.
Is there a specific kexec tools that is known to work with 2.6.14 ? Or any additional changes needed ?
Any inputs welcome , thanks in advance !!
Please CC me in reply.
Regards,Prabhakar
--- On Tue, 9/29/09, Eric W. Biederman <ebiederm@xmission.com> wrote:
From: Eric W. Biederman <ebiederm@xmission.com>
Subject: Re: [Fastboot] kexec - 2.6.14 - loads BIOS again
To: "Prabhakar K." <krishkar99@yahoo.com>
Cc: "Kexec Mailing List" <kexec@lists.infradead.org>, fastboot@lists.linux-foundation.org
Date: Tuesday, September 29, 2009, 6:11 AM
"Prabhakar K." <krishkar99@yahoo.com> writes:
>> Hi - After my previous posting I was able to make some progress.
>>
>> When I do
>>
>> kexec -l vmlinux --append="init 1 root=/dev/hda2" --console-serial
>>
>> and
>> kexec -e,
>>
>> I get message:
>>
>> Starting new kernel
>> I'm in purgatory
>>
>> And after that it still boots from BIOS (to the same first kernel).
>>
>> Whats the problem here?
>
> I would recommend instrumenting up purgatory and then your target kernel.
>
> It is quite possible the problem is in your backport.
>
>>>>>
> I have instrumented the purgatory code. when I run kexec -e, It hangs for a
> while at
> sha256_starts(&ctx); in the function verify_sha256_digest(), and then reboots
> to the first kernel (from BIOS). I have put debug prints in sha256_starts, but
> none of those are executed.
>
> Interestingly, the same function sha256_starts is executed during kexec -l,
> which is called as part of update_purgatory( )( when my_load( ) is called from
> kexec.c).
> so its surprise why the same function is giving problems when kexec -e is run.
Do you by any chance have a watchdog you are not petting?
Eric
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kexec mailing list
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http://lists.infradead.org/mailman/listinfo/kexec
^ permalink raw reply [flat|nested] 9+ messages in thread* Re: [Fastboot] kexec - 2.6.14 - loads BIOS again
2009-09-29 0:41 ` Eric W. Biederman
2009-09-29 2:48 ` Prabhakar K.
2009-09-30 19:03 ` Prabhakar K.
@ 2009-10-01 0:07 ` Prabhakar K.
2009-10-01 0:59 ` Eric W. Biederman
2 siblings, 1 reply; 9+ messages in thread
From: Prabhakar K. @ 2009-10-01 0:07 UTC (permalink / raw)
To: Eric W. Biederman; +Cc: fastboot, Kexec Mailing List
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Sending again as it is not posted yet !!
I have back ported to multiple versions of different kexec-tools. Also I disabled watchdogs so that the first kernel reboot is not kicked in.Now, with all those kexec-tools I see that it hangs after post_verification_setup_arch( ).And I had to hard reboot the router box.
Is there a specific kexec tools that is known to work with 2.6.14 ? Or any additional changes needed ?
Any inputs welcome , thanks in advance !!
Please CC me in reply.
Regards,Prabhakar
--- On Tue, 9/29/09, Eric W. Biederman <ebiederm@xmission.com> wrote:
From: Eric W. Biederman <ebiederm@xmission.com>
Subject: Re: [Fastboot] kexec - 2.6.14 - loads BIOS again
To: "Prabhakar K." <krishkar99@yahoo.com>
Cc: "Kexec Mailing List" <kexec@lists.infradead.org>, fastboot@lists.linux-foundation.org
Date: Tuesday, September 29, 2009, 6:11 AM
"Prabhakar K." <krishkar99@yahoo.com> writes:
>> Hi - After my previous posting I was able to make some progress.
>>
>> When I do
>>
>> kexec -l vmlinux --append="init 1 root=/dev/hda2" --console-serial
>>
>> and
>> kexec -e,
>>
>> I get message:
>>
>> Starting new kernel
>> I'm in purgatory
>>
>> And after that it still boots from BIOS (to the same first kernel).
>>
>> Whats the problem here?
>
> I would recommend instrumenting up purgatory and then your target kernel.
>
> It is quite possible the problem is in your backport.
>
>>>>>
> I have instrumented the purgatory code. when I run kexec -e, It hangs for a
> while at
> sha256_starts(&ctx); in the function verify_sha256_digest(), and then reboots
> to the first kernel (from BIOS). I have put debug prints in sha256_starts, but
> none of those are executed.
>
> Interestingly, the same function sha256_starts is executed during kexec -l,
> which is called as part of update_purgatory( )( when my_load( ) is called from
> kexec.c).
> so its surprise why the same function is giving problems when kexec -e is run.
Do you by any chance have a watchdog you are not petting?
Eric
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kexec mailing list
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http://lists.infradead.org/mailman/listinfo/kexec
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [Fastboot] kexec - 2.6.14 - loads BIOS again
2009-10-01 0:07 ` Prabhakar K.
@ 2009-10-01 0:59 ` Eric W. Biederman
2009-10-01 21:09 ` Prabhakar K.
0 siblings, 1 reply; 9+ messages in thread
From: Eric W. Biederman @ 2009-10-01 0:59 UTC (permalink / raw)
To: Prabhakar K.; +Cc: fastboot, Kexec Mailing List
"Prabhakar K." <krishkar99@yahoo.com> writes:
> Sending again as it is not posted yet !!
>
> I have back ported to multiple versions of different kexec-tools. Also I
> disabled watchdogs so that the first kernel reboot is not kicked in.
> Now, with all those kexec-tools I see that it hangs
> after post_verification_setup_arch( ).
> And I had to hard reboot the router box.
>
> Is there a specific kexec tools that is known to work with 2.6.14 ? Or any
> additional changes needed ?
Almost certainly if you are getting as far as kexec-tools you are dying
someplace early in your target kernel.
> Any inputs welcome , thanks in advance !!
>
> Please CC me in reply.
Eric
_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [Fastboot] kexec - 2.6.14 - loads BIOS again
2009-10-01 0:59 ` Eric W. Biederman
@ 2009-10-01 21:09 ` Prabhakar K.
2009-10-02 2:03 ` Eric W. Biederman
0 siblings, 1 reply; 9+ messages in thread
From: Prabhakar K. @ 2009-10-01 21:09 UTC (permalink / raw)
To: Eric W. Biederman; +Cc: fastboot, Kexec Mailing List
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From: Eric W. Biederman <ebiederm@xmission.com>
Subject: Re: [Fastboot] kexec - 2.6.14 - loads BIOS again
To: "Prabhakar K." <krishkar99@yahoo.com>
Cc: "Kexec Mailing List" <kexec@lists.infradead.org>, fastboot@lists.linux-foundation.org
Date: Thursday, October 1, 2009, 6:29 AM
"Prabhakar K." <krishkar99@yahoo.com> writes:
> Sending again as it is not posted yet !!
>
> I have back ported to multiple versions of different kexec-tools. Also I
> disabled watchdogs so that the first kernel reboot is not kicked in.
> Now, with all those kexec-tools I see that it hangs
> after post_verification_setup_arch( ).
> And I had to hard reboot the router box.
>
> Is there a specific kexec tools that is known to work with 2.6.14 ? Or any
> additional changes needed ?
Almost certainly if you are getting as far as kexec-tools you are dying
someplace early in your target kernel.
>>> OK. What piece of code can cause in the target kernel to die ?Can I take any working bzImage or vmlinux of a linux kernel(for that matter any linux kernel) and load that as my target kernel ? or does this has any restriction ?thanks for your input !!
> Any inputs welcome , thanks in advance !!
>
Please CC me in reply.
Eric
--- On Thu, 10/1/09, Eric W. Biederman <ebiederm@xmission.com> wrote:
From: Eric W. Biederman <ebiederm@xmission.com>
Subject: Re: [Fastboot] kexec - 2.6.14 - loads BIOS again
To: "Prabhakar K." <krishkar99@yahoo.com>
Cc: "Kexec Mailing List" <kexec@lists.infradead.org>, fastboot@lists.linux-foundation.org
Date: Thursday, October 1, 2009, 6:29 AM
"Prabhakar K." <krishkar99@yahoo.com> writes:
> Sending again as it is not posted yet !!
>
> I have back ported to multiple versions of different kexec-tools. Also I
> disabled watchdogs so that the first kernel reboot is not kicked in.
> Now, with all those kexec-tools I see that it hangs
> after post_verification_setup_arch( ).
> And I had to hard reboot the router box.
>
> Is there a specific kexec tools that is known to work with 2.6.14 ? Or any
> additional changes needed ?
Almost certainly if you are getting as far as kexec-tools you are dying
someplace early in your target kernel.
> Any inputs welcome , thanks in advance !!
>
> Please CC me in reply.
Eric
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_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec
^ permalink raw reply [flat|nested] 9+ messages in thread* Re: [Fastboot] kexec - 2.6.14 - loads BIOS again
2009-10-01 21:09 ` Prabhakar K.
@ 2009-10-02 2:03 ` Eric W. Biederman
0 siblings, 0 replies; 9+ messages in thread
From: Eric W. Biederman @ 2009-10-02 2:03 UTC (permalink / raw)
To: Prabhakar K.; +Cc: fastboot, Kexec Mailing List
"Prabhakar K." <krishkar99@yahoo.com> writes:
> From: Eric W. Biederman <ebiederm@xmission.com>
> Subject: Re: [Fastboot] kexec - 2.6.14 - loads BIOS again
> To: "Prabhakar K." <krishkar99@yahoo.com>
> Cc: "Kexec Mailing List" <kexec@lists.infradead.org>,
> fastboot@lists.linux-foundation.org
> Date: Thursday, October 1, 2009, 6:29 AM
>
> "Prabhakar K." <krishkar99@yahoo.com> writes:
>
>> Sending again as it is not posted yet !!
>>
>> I have back ported to multiple versions of different kexec-tools. Also I
>> disabled watchdogs so that the first kernel reboot is not kicked in.
>> Now, with all those kexec-tools I see that it hangs
>> after post_verification_setup_arch( ).
>> And I had to hard reboot the router box.
>>
>> Is there a specific kexec tools that is known to work with 2.6.14 ? Or any
>> additional changes needed ?
>
> Almost certainly if you are getting as far as kexec-tools you are dying
> someplace early in your target kernel.
>
>>>> OK. What piece of code can cause in the target kernel to die ?
> Can I take any working bzImage or vmlinux of a linux kernel(for that matter any
> linux kernel) and load that as my target kernel ? or does this has any
> restriction ?
Short of bugs in /sbin/kexec it is unrestricted.
Eric
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kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec
^ permalink raw reply [flat|nested] 9+ messages in thread