Re: [PATCH v2 9/9] perf cs-etm: Show a warning for an unknown magic number

[Leo Yan]

On Fri, Aug 06, 2021 at 02:41:09PM +0100, James Clark wrote:
> Currently perf reports "Cannot allocate memory" which isn't very helpful
> for a potentially user facing issue. If we add a new magic number in
> the future, perf will be able to report unrecognised magic numbers.
> 
> Signed-off-by: James Clark <james.clark@xxxxxxx>

Reviewed-by: Leo Yan <leo.yan@xxxxxxxxxx>

> ---
>  tools/perf/util/cs-etm.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c
> index 788ad5a099f6..5b276bdb96a6 100644
> --- a/tools/perf/util/cs-etm.c
> +++ b/tools/perf/util/cs-etm.c
> @@ -2973,6 +2973,11 @@ int cs_etm__process_auxtrace_info(union perf_event *event,
>  
>  			/* ETE shares first part of metadata with ETMv4 */
>  			trcidr_idx = CS_ETMV4_TRCTRACEIDR;
> +		} else {
> +			ui__error("CS ETM Trace: Unrecognised magic number %#"PRIx64". File could be from a newer version of perf.\n",
> +				  ptr[i]);
> +			err = -EINVAL;
> +			goto err_free_metadata;
>  		}
>  
>  		if (!metadata[j]) {
> -- 
> 2.28.0
>