Re: [PATCH] powerpc/crash: adjust the elfcorehdr size

[Sourabh Jain <sourabhjain@linux.ibm.com>]

On 20/02/26 15:54, Hari Bathini wrote:
>
>
> On 18/02/26 10:31 am, Sourabh Jain wrote:
>> With crash hotplug support enabled, additional memory is allocated to
>> the elfcorehdr kexec segment to accommodate resources added during
>> memory hotplug events. However, the kdump FDT is not updated with the
>> same size, which can result in elfcorehdr corruption in the kdump
>> kernel.
>>
>> Update elf_headers_sz (the kimage member representing the size of the
>> elfcorehdr kexec segment) to reflect the total memory allocated for the
>> elfcorehdr segment instead of the elfcorehdr buffer size at the time of
>> kdump load. This allows of_kexec_alloc_and_setup_fdt() to reserve the
>> full elfcorehdr memory in the kdump FDT and prevents elfcorehdr
>> corruption.
>>
>> Fixes: 849599b702ef8 ("powerpc/crash: add crash memory hotplug support")
>> Cc: Hari Bathini <hbathini@linux.ibm.com>
>> Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
>> Cc: Mahesh Salgaonkar <mahesh@linux.ibm.com>
>> Cc: Michael Ellerman <mpe@ellerman.id.au>
>> Cc: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
>> Cc: Shivang Upadhyay <shivangu@linux.ibm.com>
>> Signed-off-by: Sourabh Jain <sourabhjain@linux.ibm.com>
>> ---
>>   arch/powerpc/kexec/file_load_64.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/arch/powerpc/kexec/file_load_64.c 
>> b/arch/powerpc/kexec/file_load_64.c
>> index e7ef8b2a2554..ed76326f4b57 100644
>> --- a/arch/powerpc/kexec/file_load_64.c
>> +++ b/arch/powerpc/kexec/file_load_64.c
>> @@ -460,7 +460,7 @@ static int load_elfcorehdr_segment(struct kimage 
>> *image, struct kexec_buf *kbuf)
>>       }
>>         image->elf_load_addr = kbuf->mem;
>
>> -    image->elf_headers_sz = headers_sz;
>> +    image->elf_headers_sz = kbuf->memsz;
>
> A comment here explaining why memsz is used instead of headers_sz and
> also, another comment where memsz is set, as to why extra memory size
> is accounted under it, improves readability...

Sure I will update the commit message in the next version.

>
> Regardless..
>
> Reviewed-by: Hari Bathini <hbathini@linux.ibm.com>
Thanks for the review.

- Sourabh Jain