linux-kernel - Re: [PATCH] kexec/crash: no crash update when kexec in progress

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Message-ID: <b7a52f5b-df93-476b-a9b1-931fad1474e0@linux.ibm.com>
Date: Thu, 1 Aug 2024 13:36:46 +0530
From: Sourabh Jain <sourabhjain@...ux.ibm.com>
To: Baoquan He <bhe@...hat.com>
Cc: Hari Bathini <hbathini@...ux.ibm.com>,
        Michael Ellerman <mpe@...erman.id.au>, kexec@...ts.infradead.org,
        linux-kernel@...r.kernel.org, x86@...nel.org,
        Sachin P Bappalige <sachinpb@...ux.vnet.ibm.com>,
        linuxppc-dev@...ts.ozlabs.org
Subject: Re: [PATCH] kexec/crash: no crash update when kexec in progress

Hello Baoquan,

On 01/08/24 13:13, Baoquan He wrote:
> On 07/31/24 at 08:57pm, Sourabh Jain wrote:
>> The following errors are observed when kexec is done with SMT=off on
>> powerpc.
>>
>> [  358.458385] Removing IBM Power 842 compression device
>> [  374.795734] kexec_core: Starting new kernel
>> [  374.795748] kexec: Waking offline cpu 1.
>> [  374.875695] crash hp: kexec_trylock() failed, elfcorehdr may be inaccurate
>> [  374.935833] kexec: Waking offline cpu 2.
>> [  375.015664] crash hp: kexec_trylock() failed, elfcorehdr may be inaccurate
>> snip..
>> [  375.515823] kexec: Waking offline cpu 6.
>> [  375.635667] crash hp: kexec_trylock() failed, elfcorehdr may be inaccurate
>> [  375.695836] kexec: Waking offline cpu 7.
>>
>> During kexec, the offline CPUs are brought online, which triggers the
> Is this a generic action or specific on ppc about the offline CPUs being
> brought line during kexec?

I think it is powerpc specific.
Patch that introduced this on powerpc: e8e5c2155b003 ("powerpc/kexec: 
Fix orphaned offline CPUs across kexec")

- Sourabh Jain