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

[Hari Bathini <hbathini@linux.ibm.com>]

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...

Regardless..

Reviewed-by: Hari Bathini <hbathini@linux.ibm.com>