From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arnaldo Carvalho de Melo Subject: [PATCH 09/63] perf evsel: Always preserve errno while cleaning up perf_event_open failures Date: Thu, 7 Nov 2019 15:59:17 -0300 Message-ID: <20191107190011.23924-10-acme@kernel.org> References: <20191107190011.23924-1-acme@kernel.org> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <20191107190011.23924-1-acme@kernel.org> Sender: linux-kernel-owner@vger.kernel.org To: Ingo Molnar , Thomas Gleixner Cc: Jiri Olsa , Namhyung Kim , Clark Williams , linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, Andi Kleen , Kan Liang , Peter Zijlstra , Stephane Eranian , Arnaldo Carvalho de Melo List-Id: linux-perf-users.vger.kernel.org From: Andi Kleen 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 @@ int evsel__open(struct evsel *evsel, struct perf_cpu_map *cpus, */ 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 @@ int evsel__open(struct evsel *evsel, struct perf_cpu_map *cpus, if (err) threads->err_thread = thread; + old_errno = errno; do { while (--thread >= 0) { close(FD(evsel, cpu, thread)); @@ -1819,6 +1820,7 @@ int evsel__open(struct evsel *evsel, struct perf_cpu_map *cpus, } thread = nthreads; } while (--cpu >= 0); + errno = old_errno; return err; } -- 2.21.0