Re: [PATCH v2] powernv: don't attempt to refetch the FSP dump until the user has explicitly acked it.

[Michael Neuling <mikey@neuling.org>]

Stewart Smith <stewart@linux.vnet.ibm.com> wrote:

> This fixes a bug where we would get two events from OPAL with DUMP_AVAIL
> set (which is valid for OPAL to do) and in the second run of extract_dump()
> we would fail to free the memory previously allocated for the dump
> (leaking ~6MB+) as well as on the second dump_read_data() call OPAL
> would not retrieve the dump, leaving us with a dump in linux that was
> the correct size but all zeros.
> 
> Changes since v1: fixed typo
> 
> Signed-off-by: Stewart Smith <stewart@linux.vnet.ibm.com>
> Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

Should we CC stable on this?

Mikey

> ---
>  arch/powerpc/platforms/powernv/opal-dump.c |    8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/arch/powerpc/platforms/powernv/opal-dump.c b/arch/powerpc/platforms/powernv/opal-dump.c
> index 4447027..53c2675 100644
> --- a/arch/powerpc/platforms/powernv/opal-dump.c
> +++ b/arch/powerpc/platforms/powernv/opal-dump.c
> @@ -238,6 +238,14 @@ static int extract_dump(void)
>  {
>  	int rc;
>  
> +	/* We can get notified that a dump is available multiple times
> +	 * (dump_read_info clears the bit in the event from OPAL).
> +	 * But we should not re-read the dump from OPAL as we
> +	 * don't get the next dump until we've explicitly acked this one.
> +	 */
> +	if (dump_avail)
> +		return OPAL_SUCCESS;
> +
>  	/* Get dump ID, size */
>  	rc = dump_read_info();
>  	if (rc != OPAL_SUCCESS)
> -- 
> 1.7.10.4
> 
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