perf hists: Fix an invalid memory free on he->branch_info

The branch info was allocated for the whole stack and passed matching
hist entry for each level during processing samples.  Thus when a hist
entry tries to free its branch info like in hists__collapse_insert_entry
it'll face following error.

  *** glibc detected *** perf: munmap_chunk(): invalid pointer: 0x00000000014e9d20 ***
  ======= Backtrace: =========
  /lib64/libc.so.6[0x387d47ae16]
  perf[0x4923bd]
  perf(cmd_report+0xd68)[0x432a08]
  perf[0x41a663]
  perf(main+0x58f)[0x419eaf]
  /lib64/libc.so.6(__libc_start_main+0xf5)[0x387d421735]
  perf[0x419f95]

Fix it by allocating and copying branch info for each new hist entry.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1364816125-12212-2-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

2 files changed, 20 insertions, 3 deletions

diff --git a/tools/perf/builtin-report.c b/tools/perf/builtin-report.c
index bd0ca81eeaca..d9f2de3e81fe 100644
--- a/tools/perf/builtin-report.c
+++ b/tools/perf/builtin-report.c
@@ -187,6 +187,9 @@ static int perf_report__add_branch_hist_entry(struct perf_tool *tool,
         for (i = 0; i < sample->branch_stack->nr; i++) {
                 if (rep->hide_unresolved && !(bi[i].from.sym && bi[i].to.sym))
                         continue;
+
+                err = -ENOMEM;
+
                 /*
                  * The report shows the percentage of total branches captured
                  * and not events sampled. Thus we use a pseudo period of 1.
@@ -195,7 +198,6 @@ static int perf_report__add_branch_hist_entry(struct perf_tool *tool,
                                 &bi[i], 1, 1);
                 if (he) {
                         struct annotation *notes;
-                        err = -ENOMEM;
                         bx = he->branch_info;
                         if (bx->from.sym && use_browser == 1 && sort__has_sym) {
                                 notes = symbol__annotation(bx->from.sym);
@@ -226,11 +228,12 @@ static int perf_report__add_branch_hist_entry(struct perf_tool *tool,
                         }
                         evsel->hists.stats.total_period += 1;
                         hists__inc_nr_events(&evsel->hists, PERF_RECORD_SAMPLE);
-                        err = 0;
                 } else
-                        return -ENOMEM;
+                        goto out;
         }
+        err = 0;
 out:
+        free(bi);
         return err;
 }
 
diff --git a/tools/perf/util/hist.c b/tools/perf/util/hist.c
index 6b32721f829a..9438d576459d 100644
--- a/tools/perf/util/hist.c
+++ b/tools/perf/util/hist.c
@@ -292,6 +292,20 @@ static struct hist_entry *hist_entry__new(struct hist_entry *template)
                         he->ms.map->referenced = true;
 
                 if (he->branch_info) {
+                        /*
+                         * This branch info is (a part of) allocated from
+                         * machine__resolve_bstack() and will be freed after
+                         * adding new entries.  So we need to save a copy.
+                         */
+                        he->branch_info = malloc(sizeof(*he->branch_info));
+                        if (he->branch_info == NULL) {
+                                free(he);
+                                return NULL;
+                        }
+
+                        memcpy(he->branch_info, template->branch_info,
+                               sizeof(*he->branch_info));
+
                         if (he->branch_info->from.map)
                                 he->branch_info->from.map->referenced = true;
                         if (he->branch_info->to.map)