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[45.33.10.79]) by smtp.gmail.com with ESMTPSA id 61sm5139805otx.8.2019.07.02.03.35.57 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 02 Jul 2019 03:36:04 -0700 (PDT) From: Leo Yan To: Arnaldo Carvalho de Melo , Peter Zijlstra , Ingo Molnar , Alexander Shishkin , Jiri Olsa , Namhyung Kim , Mathieu Poirier , Suzuki K Poulose , Andi Kleen , "David S. Miller" , Davidlohr Bueso , Rasmus Villemoes , Jin Yao , Song Liu , Adrian Hunter , Alexios Zavras , Thomas Gleixner , Changbin Du , Eric Saint-Etienne , Konstantin Khlebnikov , Thomas Richter , Alexey Budankov , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Cc: Leo Yan Subject: [PATCH v1 10/11] perf intel-pt: Smatch: Fix potential NULL pointer dereference Date: Tue, 2 Jul 2019 18:34:19 +0800 Message-Id: <20190702103420.27540-11-leo.yan@linaro.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190702103420.27540-1-leo.yan@linaro.org> References: <20190702103420.27540-1-leo.yan@linaro.org> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Based on the following report from Smatch, fix the potential NULL pointer dereference check. tools/perf/util/intel-pt.c:3200 intel_pt_process_auxtrace_info() error: we previously assumed 'session->itrace_synth_opts' could be null (see line 3196) tools/perf/util/intel-pt.c:3206 intel_pt_process_auxtrace_info() warn: variable dereferenced before check 'session->itrace_synth_opts' (see line 3200) tools/perf/util/intel-pt.c 3196 if (session->itrace_synth_opts && session->itrace_synth_opts->set) { 3197 pt->synth_opts = *session->itrace_synth_opts; 3198 } else { 3199 itrace_synth_opts__set_default(&pt->synth_opts, 3200 session->itrace_synth_opts->default_no_sample); ^^^^^^^^^^^^^^^^^^^^^^^^^^ 3201 if (!session->itrace_synth_opts->default_no_sample && 3202 !session->itrace_synth_opts->inject) { 3203 pt->synth_opts.branches = false; 3204 pt->synth_opts.callchain = true; 3205 } 3206 if (session->itrace_synth_opts) ^^^^^^^^^^^^^^^^^^^^^^^^^^ 3207 pt->synth_opts.thread_stack = 3208 session->itrace_synth_opts->thread_stack; 3209 } To dismiss the potential NULL pointer dereference, this patch validates the pointer 'session->itrace_synth_opts' before access its elements. Signed-off-by: Leo Yan --- tools/perf/util/intel-pt.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/tools/perf/util/intel-pt.c b/tools/perf/util/intel-pt.c index 550db6e77968..88b567bdf1f9 100644 --- a/tools/perf/util/intel-pt.c +++ b/tools/perf/util/intel-pt.c @@ -3195,7 +3195,7 @@ int intel_pt_process_auxtrace_info(union perf_event *event, if (session->itrace_synth_opts && session->itrace_synth_opts->set) { pt->synth_opts = *session->itrace_synth_opts; - } else { + } else if (session->itrace_synth_opts) { itrace_synth_opts__set_default(&pt->synth_opts, session->itrace_synth_opts->default_no_sample); if (!session->itrace_synth_opts->default_no_sample && @@ -3203,8 +3203,7 @@ int intel_pt_process_auxtrace_info(union perf_event *event, pt->synth_opts.branches = false; pt->synth_opts.callchain = true; } - if (session->itrace_synth_opts) - pt->synth_opts.thread_stack = + pt->synth_opts.thread_stack = session->itrace_synth_opts->thread_stack; } -- 2.17.1