Messages in this thread Patch in this message | | | From | 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 |
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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 <leo.yan@linaro.org> --- 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
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