linux-kernel - Re: [PATCH 2/2] perf: cs-etm: Fix corrupt inject files when only last branch option is enabled

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Date:   Sat, 12 Feb 2022 00:05:16 +0800
From:   Leo Yan <leo.yan@...aro.org>
To:     James Clark <james.clark@....com>
Cc:     acme@...nel.org, linux-perf-users@...r.kernel.org,
        mathieu.poirier@...aro.org, coresight@...ts.linaro.org,
        Mike Leach <mike.leach@...aro.org>,
        John Garry <john.garry@...wei.com>,
        Will Deacon <will@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Jiri Olsa <jolsa@...hat.com>,
        Namhyung Kim <namhyung@...nel.org>,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/2] perf: cs-etm: Fix corrupt inject files when only
 last branch option is enabled

On Thu, Feb 10, 2022 at 08:06:20PM +0000, James Clark wrote:
> Perf inject with Coresight data generates files that cannot be opened
> when only the last branch option is specified:
> 
>   perf inject -i perf.data --itrace=l -o inject.data
>   perf script -i inject.data
>   0x33faa8 [0x8]: failed to process type: 9 [Bad address]
> 
> This is because cs_etm__synth_instruction_sample() is called even when
> the sample type for instructions hasn't been setup. Last branch records
> are attached to instruction samples so it doesn't make sense to generate
> them when --itrace=i isn't specified anyway.
> 
> This change disables all calls of cs_etm__synth_instruction_sample()
> unless --itrace=i is specified, resulting in a file with no samples if
> only --itrace=l is provided, rather than a bad file.
> 
> Signed-off-by: James Clark <james.clark@....com>

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

> ---
>  tools/perf/util/cs-etm.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c
> index 796a065a500e..8b95fb3c4d7b 100644
> --- a/tools/perf/util/cs-etm.c
> +++ b/tools/perf/util/cs-etm.c
> @@ -1553,6 +1553,7 @@ static int cs_etm__flush(struct cs_etm_queue *etmq,
>  		goto swap_packet;
>  
>  	if (etmq->etm->synth_opts.last_branch &&
> +	    etmq->etm->synth_opts.instructions &&
>  	    tidq->prev_packet->sample_type == CS_ETM_RANGE) {
>  		u64 addr;
>  
> @@ -1610,6 +1611,7 @@ static int cs_etm__end_block(struct cs_etm_queue *etmq,
>  	 * the trace.
>  	 */
>  	if (etmq->etm->synth_opts.last_branch &&
> +	    etmq->etm->synth_opts.instructions &&
>  	    tidq->prev_packet->sample_type == CS_ETM_RANGE) {
>  		u64 addr;
>  
> -- 
> 2.28.0
>