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 <[email protected]> Cc: Arnaldo Carvalho de Melo <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Frederic Weisbecker <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Jiri Olsa <[email protected]> Cc: Namhyung Kim <[email protected]> Cc: Stephane Eranian <[email protected]> --- 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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
