From: Jiri Olsa <[email protected]>

Bail out without error if we want to do backtrace post unwind, but were
not able to capture user registers or user stack during the record
phase, which is possible and valid case.

Signed-off-by: Jiri Olsa <[email protected]>
Cc: Frederic Weisbecker <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Link: 
http://lkml.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
---
 tools/perf/util/session.c |    5 +++++
 1 file changed, 5 insertions(+)

diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
index 3806ea4..0ecd62b 100644
--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -388,6 +388,11 @@ int machine__resolve_callchain(struct machine *machine,
              (evsel->attr.sample_type & PERF_SAMPLE_STACK_USER)))
                return 0;
 
+       /* Bail out if nothing was captured. */
+       if ((!sample->user_regs.regs) ||
+           (!sample->user_stack.size))
+               return 0;
+
        return unwind__get_entries(unwind_entry, &callchain_cursor, machine,
                                   thread, evsel->attr.sample_regs_user,
                                   sample);
-- 
1.7.9.2.358.g22243

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