From 796c01a4bfb4b35ec6d1bd1cd5d520515d078b51 Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Sun, 20 Oct 2019 10:51:54 -0700 Subject: [PATCH] perf evsel: Always preserve errno while cleaning up perf_event_open failures In some cases when perf_event_open fails, it may do some closes to clean up. In special cases these closes can fail too, which overwrites the errno of the perf_event_open, which is then incorrectly reported. Save/restore errno around closes. Signed-off-by: Andi Kleen Acked-by: Jiri Olsa Cc: Kan Liang Cc: Peter Zijlstra Cc: Stephane Eranian Link: http://lore.kernel.org/lkml/20191020175202.32456-2-andi@firstfloor.org Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/evsel.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c index abc7fda4a0fe..d831038b55f2 100644 --- a/tools/perf/util/evsel.c +++ b/tools/perf/util/evsel.c @@ -1574,7 +1574,7 @@ int evsel__open(struct evsel *evsel, struct perf_cpu_map *cpus, { int cpu, thread, nthreads; unsigned long flags = PERF_FLAG_FD_CLOEXEC; - int pid = -1, err; + int pid = -1, err, old_errno; enum { NO_CHANGE, SET_TO_MAX, INCREASED_MAX } set_rlimit = NO_CHANGE; if ((perf_missing_features.write_backward && evsel->core.attr.write_backward) || @@ -1727,8 +1727,8 @@ try_fallback: */ if (err == -EMFILE && set_rlimit < INCREASED_MAX) { struct rlimit l; - int old_errno = errno; + old_errno = errno; if (getrlimit(RLIMIT_NOFILE, &l) == 0) { if (set_rlimit == NO_CHANGE) l.rlim_cur = l.rlim_max; @@ -1812,6 +1812,7 @@ out_close: if (err) threads->err_thread = thread; + old_errno = errno; do { while (--thread >= 0) { close(FD(evsel, cpu, thread)); @@ -1819,6 +1820,7 @@ out_close: } thread = nthreads; } while (--cpu >= 0); + errno = old_errno; return err; } -- 2.11.0