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Date:   Tue, 18 Apr 2023 12:26:04 -0300
From:   Arnaldo Carvalho de Melo <acme@kernel.org>
To:     James Clark <james.clark@arm.com>
Cc:     linux-perf-users@vger.kernel.org,
        Mathieu Poirier <mathieu.poirier@linaro.org>,
        Suzuki K Poulose <suzuki.poulose@arm.com>,
        Mike Leach <mike.leach@linaro.org>,
        Leo Yan <leo.yan@linaro.org>,
        John Garry <john.g.garry@oracle.com>,
        Will Deacon <will@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@redhat.com>,
        Mark Rutland <mark.rutland@arm.com>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Jiri Olsa <jolsa@kernel.org>,
        Namhyung Kim <namhyung@kernel.org>,
        Ian Rogers <irogers@google.com>,
        Adrian Hunter <adrian.hunter@intel.com>,
        coresight@lists.linaro.org, linux-arm-kernel@lists.infradead.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH] perf: cs-etm: Fix segfault in dso lookup
Message-ID: <ZD62jJiGaKmqcWom@kernel.org>
References: <20230418141203.673465-1-james.clark@arm.com>
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Em Tue, Apr 18, 2023 at 03:12:03PM +0100, James Clark escreveu:
> map__dso() is called before thread__find_map() which always results in a
> null pointer dereference. Fix it by finding first, then checking if it
> exists.
> 
> Fixes: 63df0e4bc368 ("perf map: Add accessor for dso")

Thanks, applied, checking if another such pattern slipped by in that
cset.

- Arnaldo

> Signed-off-by: James Clark <james.clark@arm.com>
> ---
>  tools/perf/util/cs-etm.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c
> index 103865968700..8dd81ddd9e4e 100644
> --- a/tools/perf/util/cs-etm.c
> +++ b/tools/perf/util/cs-etm.c
> @@ -885,9 +885,11 @@ static u32 cs_etm__mem_access(struct cs_etm_queue *etmq, u8 trace_chan_id,
>  		thread = etmq->etm->unknown_thread;
>  	}
>  
> -	dso = map__dso(al.map);
> +	if (!thread__find_map(thread, cpumode, address, &al))
> +		return 0;
>  
> -	if (!thread__find_map(thread, cpumode, address, &al) || !dso)
> +	dso = map__dso(al.map);
> +	if (!dso)
>  		return 0;
>  
>  	if (dso->data.status == DSO_DATA_STATUS_ERROR &&
> -- 
> 2.34.1
> 

-- 

- Arnaldo