Commit-ID:  323fd749821daab0f327ec86d707c4542963cdb0
Gitweb:     https://git.kernel.org/tip/323fd749821daab0f327ec86d707c4542963cdb0
Author:     Leo Yan <leo....@linaro.org>
AuthorDate: Mon, 8 Jul 2019 22:39:36 +0800
Committer:  Arnaldo Carvalho de Melo <a...@redhat.com>
CommitDate: Tue, 9 Jul 2019 10:13:28 -0300

perf intel-pt: Fix potential NULL pointer dereference found by the smatch tool

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         }

'session->itrace_synth_opts' is impossible to be a NULL pointer in
intel_pt_process_auxtrace_info(), thus this patch removes the NULL test
for 'session->itrace_synth_opts'.

Signed-off-by: Leo Yan <leo....@linaro.org>
Acked-by: Adrian Hunter <adrian.hun...@intel.com>
Cc: Alexander Shishkin <alexander.shish...@linux.intel.com>
Cc: Andi Kleen <a...@linux.intel.com>
Cc: Jiri Olsa <jo...@redhat.com>
Cc: Mathieu Poirier <mathieu.poir...@linaro.org>
Cc: Namhyung Kim <namhy...@kernel.org>
Cc: Suzuki Poulouse <suzuki.poul...@arm.com>
Cc: linux-arm-ker...@lists.infradead.org
Link: http://lkml.kernel.org/r/20190708143937.7722-4-leo....@linaro.org
Signed-off-by: Arnaldo Carvalho de Melo <a...@redhat.com>
---
 tools/perf/util/intel-pt.c | 13 +++++--------
 1 file changed, 5 insertions(+), 8 deletions(-)

diff --git a/tools/perf/util/intel-pt.c b/tools/perf/util/intel-pt.c
index c76a96f777fb..df061599fef4 100644
--- a/tools/perf/util/intel-pt.c
+++ b/tools/perf/util/intel-pt.c
@@ -3210,7 +3210,7 @@ int intel_pt_process_auxtrace_info(union perf_event 
*event,
                goto err_delete_thread;
        }
 
-       if (session->itrace_synth_opts && session->itrace_synth_opts->set) {
+       if (session->itrace_synth_opts->set) {
                pt->synth_opts = *session->itrace_synth_opts;
        } else {
                itrace_synth_opts__set_default(&pt->synth_opts,
@@ -3220,8 +3220,7 @@ 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;
        }
 
@@ -3241,11 +3240,9 @@ int intel_pt_process_auxtrace_info(union perf_event 
*event,
                pt->cbr2khz = tsc_freq / pt->max_non_turbo_ratio / 1000;
        }
 
-       if (session->itrace_synth_opts) {
-               err = intel_pt_setup_time_ranges(pt, 
session->itrace_synth_opts);
-               if (err)
-                       goto err_delete_thread;
-       }
+       err = intel_pt_setup_time_ranges(pt, session->itrace_synth_opts);
+       if (err)
+               goto err_delete_thread;
 
        if (pt->synth_opts.calls)
                pt->branches_filter |= PERF_IP_FLAG_CALL | PERF_IP_FLAG_ASYNC |

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