perf record: Robustify perf_event__synth_time_conv()

It is possible that all events in an evlist are overwritable.
perf_event__synth_time_conv() should not crash in this case.
record__pick_pc() is used to check avaliability.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1464056944-166978-3-git-send-email-wangnan0@huawei.com
Signed-off-by: He Kuang <hekuang@huawei.com>
[ Split from a larger patch ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/arch/x86/util/tsc.c b/tools/perf/arch/x86/util/tsc.c
index 357f1b13b5ae3e585aa609e303e08bd6f344d546..2e5567c94e09430f86db124a9a0fa1a05799943d 100644 (file)
--- a/tools/perf/arch/x86/util/tsc.c
+++ b/tools/perf/arch/x86/util/tsc.c
@@ -62,6 +62,8 @@ int perf_event__synth_time_conv(const struct perf_event_mmap_page *pc,
        struct perf_tsc_conversion tc;
        int err;
 
+       if (!pc)
+               return 0;
        err = perf_read_tsc_conversion(pc, &tc);
        if (err == -EOPNOTSUPP)
                return 0;

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index dc3fcb597e4c10cf091dcad73a53776387baab16..d4cf1b0c88f91703dba0785a06f5dd9b86ee4799 100644 (file)
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -655,6 +655,13 @@ perf_event__synth_time_conv(const struct perf_event_mmap_page *pc __maybe_unused
        return 0;
 }
 
+static const struct perf_event_mmap_page *record__pick_pc(struct record *rec)
+{
+       if (rec->evlist && rec->evlist->mmap && rec->evlist->mmap[0].base)
+               return rec->evlist->mmap[0].base;
+       return NULL;
+}
+
 static int record__synthesize(struct record *rec)
 {
        struct perf_session *session = rec->session;
@@ -692,7 +699,7 @@ static int record__synthesize(struct record *rec)
                }
        }
 
-       err = perf_event__synth_time_conv(rec->evlist->mmap[0].base, tool,
+       err = perf_event__synth_time_conv(record__pick_pc(rec), tool,
                                          process_synthesized_event, machine);
        if (err)
                goto out;