From: Jiri Olsa <[email protected]> We need to fail the event ID retrieval in case both following conditions are true:
- we are on kernel with no PERF_EVENT_IOC_ID support - PERF_FORMAT_GROUP read format is set The PERF_FORMAT_GROUP read format bit is the killer for retrieving event ID out of the read syscall, because we have no guarantee of the event placement within leader kernel sibling list. Signed-off-by: Jiri Olsa <[email protected]> Acked-by: Namhyung Kim <[email protected]> Cc: Corey Ashford <[email protected]> Cc: Frederic Weisbecker <[email protected]> Cc: Namhyung Kim <[email protected]> Cc: Paul Mackerras <[email protected]> Cc: Peter Zijlstra <[email protected]> Link: http://lkml.kernel.org/n/[email protected] Signed-off-by: Arnaldo Carvalho de Melo <[email protected]> --- tools/perf/util/evlist.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c index df77a44..10fcc03 100644 --- a/tools/perf/util/evlist.c +++ b/tools/perf/util/evlist.c @@ -314,6 +314,13 @@ static int perf_evlist__id_add_fd(struct perf_evlist *evlist, /* Legacy way to get event id.. All hail to old kernels! */ + /* + * This way does not work with group format read, so bail + * out in that case. + */ + if (perf_evlist__read_format(evlist) & PERF_FORMAT_GROUP) + return -1; + if (!(evsel->attr.read_format & PERF_FORMAT_ID) || read(fd, &read_data, sizeof(read_data)) == -1) return -1; -- 1.8.1.4 -- 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/
