From: Andi Kleen <andi@firstfloor.org>
To: acme@kernel.org
Cc: jolsa@kernel.org, eranian@google.com, kan.liang@linux.intel.com,
peterz@infradead.org, linux-kernel@vger.kernel.org,
Andi Kleen <ak@linux.intel.com>
Subject: [PATCH v1 1/9] perf evsel: Always preserve errno while cleaning up perf_event_open failures
Date: Sun, 20 Oct 2019 09:13:38 -0700 [thread overview]
Message-ID: <20191020161346.18938-2-andi@firstfloor.org> (raw)
In-Reply-To: <20191020161346.18938-1-andi@firstfloor.org>
From: Andi Kleen <ak@linux.intel.com>
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>
---
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 85825384f9e8..a646975a20f3 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -1740,7 +1740,7 @@ 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) ||
@@ -1893,8 +1893,8 @@ 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;
@@ -1978,6 +1978,7 @@ 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));
@@ -1985,6 +1986,7 @@ int evsel__open(struct evsel *evsel, struct perf_cpu_map *cpus,
}
thread = nthreads;
} while (--cpu >= 0);
+ errno = old_errno;
return err;
}
--
2.21.0
next prev parent reply other threads:[~2019-10-20 16:14 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-20 16:13 Optimize perf stat for large number of events/cpus v1 Andi Kleen
2019-10-20 16:13 ` Andi Kleen [this message]
2019-10-20 16:13 ` [PATCH v1 2/9] perf evsel: Avoid close(-1) Andi Kleen
2019-10-20 16:13 ` [PATCH v1 3/9] perf pmu: Use file system cache to optimize sysfs access Andi Kleen
2019-10-20 16:13 ` [PATCH v1 4/9] perf affinity: Add infrastructure to save/restore affinity Andi Kleen
2019-10-20 16:13 ` [PATCH v1 5/9] perf evsel: Add iterator to iterate over events ordered by CPU Andi Kleen
2019-10-20 16:13 ` [PATCH v1 6/9] perf stat: Use affinity for closing file descriptors Andi Kleen
2019-10-20 16:13 ` [PATCH v1 7/9] perf stat: Use affinity for opening events Andi Kleen
2019-10-20 16:13 ` [PATCH v1 8/9] perf stat: Use affinity for reading Andi Kleen
2019-10-20 16:13 ` [PATCH v1 9/9] perf stat: Use affinity for enabling/disabling events Andi Kleen
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