Recovery algorithm in __perf_session__process_events attempts to remap
a perf.data file with a different file_offset and try again at a new head
position. Both of these adjustment rely on page_offset. If page_offset is
0 then file_offset and head never change which means the remap attempt is
the same and the fetch_mmaped_event is the same and the processing just
loops forever.
Detect this condition and warn the user.
Signed-off-by: David Ahern <dsah...@gmail.com>
Cc: Arnaldo Carvalho de Melo <a...@ghostprotocols.net>
Cc: Ingo Molnar <mi...@kernel.org>
Cc: Frederic Weisbecker <fweis...@gmail.com>
Cc: Peter Zijlstra <pet...@infradead.org>
Cc: Jiri Olsa <jo...@redhat.com>
Cc: Namhyung Kim <namhy...@kernel.org>
Cc: Stephane Eranian <eran...@google.com>
---
tools/perf/util/session.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
index cf1fe01..1c4dc45 100644
--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -1235,6 +1235,12 @@ more:
}
page_offset = page_size * (head / page_size);
+ /* catch looping where we never make forward progress. */
+ if (page_offset == 0) {
+ pr_err("Loop detection processing events. Is file
corrupted?\n");
+ return -1;
+ }
+
file_offset += page_offset;
head -= page_offset;
goto remap;
--
1.7.10.1
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