[PATCH 2/2] perf tools: report PERF_FLAG_FD_CLOEXEC probing error once

From: Yann Droneaud
Date: Sat Sep 13 2014 - 06:39:44 EST


In case of failure, unrelated to PERF_FLAG_FD_CLOEXEC,
perf_flag_probe() reports the error twice. For example:

$ perf record ls
Error:
perf_event_open(..., PERF_FLAG_FD_CLOEXEC) failed with unexpected error 16 (Device or resource busy)
perf_event_open(..., 0) failed unexpectedly with error 16 (Device or resource busy)

There's no need for the second error message, so this
patch changes the function to only report a second
error message when the two calls to perf_even_open(2)
fail with different error codes.

Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Cc: David Ahern <dsahern@xxxxxxxxx>
Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Stephane Eranian <eranian@xxxxxxxxxx>
Cc: William Cohen <wcohen@xxxxxxxxxx>
Reported-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Link: http://lkml.kernel.org/r/1406908014-8312-1-git-send-email-jolsa@xxxxxxxxxx
Link: http://lkml.kernel.org/r/cover.1410595700.git.ydroneaud@xxxxxxxxxx
Signed-off-by: Yann Droneaud <ydroneaud@xxxxxxxxxx>
---
tools/perf/util/cloexec.c | 26 ++++++++++++++------------
1 file changed, 14 insertions(+), 12 deletions(-)

diff --git a/tools/perf/util/cloexec.c b/tools/perf/util/cloexec.c
index 6b948e05e5f0..91331b4ffc3d 100644
--- a/tools/perf/util/cloexec.c
+++ b/tools/perf/util/cloexec.c
@@ -16,7 +16,7 @@ static int perf_flag_probe(void)
.exclude_kernel = 1,
};
int fd;
- int err;
+ int err0, err1;
int cpu;
pid_t pid = -1;
char sbuf[STRERR_BUFSIZE];
@@ -35,7 +35,7 @@ static int perf_flag_probe(void)
}
break;
}
- err = errno;
+ err0 = errno;

if (fd >= 0) {
close(fd);
@@ -43,25 +43,27 @@ static int perf_flag_probe(void)
}

/* ignore busy errors */
- if (err == EBUSY)
+ if (err0 == EBUSY)
return -1;

- WARN_ONCE(err != EINVAL,
+ WARN_ONCE(err0 != EINVAL,
"perf_event_open(..., PERF_FLAG_FD_CLOEXEC) failed with unexpected error %d (%s)\n",
- err, strerror_r(err, sbuf, sizeof(sbuf)));
+ err0, strerror_r(err0, sbuf, sizeof(sbuf)));

/* not supported, confirm error related to PERF_FLAG_FD_CLOEXEC */
fd = sys_perf_event_open(&attr, pid, cpu, -1, 0);
- err = errno;
+ err1 = errno;

- if (WARN_ONCE(fd < 0,
- "perf_event_open(..., 0) failed unexpectedly with error %d (%s)\n",
- err, strerror_r(err, sbuf, sizeof(sbuf))))
- return -1;
+ if (fd >= 0) {
+ close(fd);
+ return 0;
+ }

- close(fd);
+ WARN_ONCE(err0 != err1,
+ "perf_event_open(..., 0) failed unexpectedly with error %d (%s)\n",
+ err1, strerror_r(err1, sbuf, sizeof(sbuf)));

- return 0;
+ return -1;
}

unsigned long perf_event_open_cloexec_flag(void)
--
1.9.3

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/