Re: [PATCH v4 3/7] powerpc/fadump: un-register fadump on kexec path.

[Nicholas Piggin <nicholas.piggin@gmail.com>]

On Fri, 20 Apr 2018 10:34:35 +0530
Mahesh J Salgaonkar <mahesh@linux.vnet.ibm.com> wrote:

> From: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
> 
> otherwise the fadump registration in new kexec-ed kernel complains that
> fadump is already registered. This makes new kernel to continue using
> fadump registered by previous kernel which may lead to invalid vmcore
> generation. Hence this patch fixes this issue by un-registering fadump
> in fadump_cleanup() which is called during kexec path so that new kernel
> can register fadump with new valid values.

Is this a bug fix that should go to previous kernels as well?

> 
> Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
> ---
>  arch/powerpc/kernel/fadump.c |    3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/arch/powerpc/kernel/fadump.c b/arch/powerpc/kernel/fadump.c
> index 43bfa535d0ea..16b3e8c5cae0 100644
> --- a/arch/powerpc/kernel/fadump.c
> +++ b/arch/powerpc/kernel/fadump.c
> @@ -1276,6 +1276,9 @@ void fadump_cleanup(void)
>  	/* Invalidate the registration only if dump is active. */
>  	if (fw_dump.dump_active) {
>  		fadump_invalidate_dump(fdm_active);
> +	} else if (fw_dump.dump_registered) {
> +		/* Un-register Firmware-assisted dump if it was registered. */
> +		fadump_unregister_dump(&fdm);
>  	}
>  }
>  
>