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Subject: Re: [PATCH 4/4] perf intel-pt/bts: fix potential NULL pointer
 dereference in intel_bts_process_auxtrace_info
To:     Wen Yang <wen.yang99@zte.com.cn>, peterz@infradead.org
Cc:     mingo@redhat.com, acme@kernel.org,
        alexander.shishkin@linux.intel.com, jolsa@redhat.com,
        namhyung@kernel.org, ak@linux.intel.com,
        linux-kernel@vger.kernel.org, zhong.weidong@zte.com.cn,
        wang.yi59@zte.com.cn, Julia Lawall <julia.lawall@lip6.fr>
References: <1542786220-19338-1-git-send-email-wen.yang99@zte.com.cn>
From:   Adrian Hunter <adrian.hunter@intel.com>
Organization: Intel Finland Oy, Registered Address: PL 281, 00181 Helsinki,
 Business Identity Code: 0357606 - 4, Domiciled in Helsinki
Message-ID: <60a8972e-037f-8d6b-ce45-76b65a841156@intel.com>
Date:   Wed, 21 Nov 2018 11:13:24 +0200
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On 21/11/18 9:43 AM, Wen Yang wrote:
> This patch fixes a possible null pointer dereference in
> intel_bts_process_auxtrace_info, detected by the semantic patch
> deref_null.cocci, with the following warning:
> 
> ./tools/perf/util/intel-bts.c:921:32-49: ERROR: session -> itrace_synth_opts is NULL but dereferenced.
> 
> Signed-off-by: Wen Yang <wen.yang99@zte.com.cn>
> Reviewed-by: Tan Hu <tan.hu@zte.com.cn>
> CC: Julia Lawall <julia.lawall@lip6.fr>
> ---
>  tools/perf/util/intel-bts.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/tools/perf/util/intel-bts.c b/tools/perf/util/intel-bts.c
> index 7b27d77..b0258f4 100644
> --- a/tools/perf/util/intel-bts.c
> +++ b/tools/perf/util/intel-bts.c
> @@ -917,7 +917,8 @@ int intel_bts_process_auxtrace_info(union perf_event *event,
>  	if (session->itrace_synth_opts && session->itrace_synth_opts->set) {
>  		bts->synth_opts = *session->itrace_synth_opts;
>  	} else {
> -		itrace_synth_opts__set_default(&bts->synth_opts,
> +		if (session->itrace_synth_opts)
> +			itrace_synth_opts__set_default(&bts->synth_opts,
>  				session->itrace_synth_opts->default_no_sample);
>  		if (session->itrace_synth_opts)
>  			bts->synth_opts.thread_stack =
> 

See response to patch 1.