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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 <ak@linux.intel.com> Acked-by: Jiri Olsa <jolsa@kernel.org> Cc: Kan Liang <kan.liang@linux.intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Link: http://lore.kernel.org/lkml/20191020175202.32456-2-andi@firstfloor.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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@ -1574,7 +1574,7 @@ int evsel__open(struct evsel *evsel, struct perf_cpu_map *cpus,
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{
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int cpu, thread, nthreads;
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unsigned long flags = PERF_FLAG_FD_CLOEXEC;
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int pid = -1, err;
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int pid = -1, err, old_errno;
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enum { NO_CHANGE, SET_TO_MAX, INCREASED_MAX } set_rlimit = NO_CHANGE;
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if ((perf_missing_features.write_backward && evsel->core.attr.write_backward) ||
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@ -1727,8 +1727,8 @@ int evsel__open(struct evsel *evsel, struct perf_cpu_map *cpus,
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*/
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if (err == -EMFILE && set_rlimit < INCREASED_MAX) {
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struct rlimit l;
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int old_errno = errno;
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old_errno = errno;
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if (getrlimit(RLIMIT_NOFILE, &l) == 0) {
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if (set_rlimit == NO_CHANGE)
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l.rlim_cur = l.rlim_max;
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@ -1812,6 +1812,7 @@ int evsel__open(struct evsel *evsel, struct perf_cpu_map *cpus,
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if (err)
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threads->err_thread = thread;
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old_errno = errno;
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do {
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while (--thread >= 0) {
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close(FD(evsel, cpu, thread));
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@ -1819,6 +1820,7 @@ int evsel__open(struct evsel *evsel, struct perf_cpu_map *cpus,
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}
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thread = nthreads;
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} while (--cpu >= 0);
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errno = old_errno;
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return err;
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}
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