diff options
| author | Adrian Hunter | 2015-02-24 13:20:59 +0200 |
|---|---|---|
| committer | Arnaldo Carvalho de Melo | 2015-02-25 16:40:13 -0300 |
| commit | 48536c9195ae8c2a00fd8f400bac72ab613feaab (patch) | |
| tree | 59621cfff58dca6939d0cb780e3857d416bad2b7 /tools | |
| parent | 95a09cfa3cdf94231ce511f1697754482b918d39 (diff) | |
perf tools: Fix probing for PERF_FLAG_FD_CLOEXEC flag
Commit f6edb53c4993ffe92ce521fb449d1c146cea6ec2 converted the probe to
a CPU wide event first (pid == -1). For kernels that do not support
the PERF_FLAG_FD_CLOEXEC flag the probe fails with EINVAL. Since this
errno is not handled pid is not reset to 0 and the subsequent use of
pid = -1 as an argument brings in an additional failure path if
perf_event_paranoid > 0:
$ perf record -- sleep 1
perf_event_open(..., 0) failed unexpectedly with error 13 (Permission denied)
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.007 MB /tmp/perf.data (11 samples) ]
Also, ensure the fd of the confirmation check is closed and comment why
pid = -1 is used.
Needs to go to 3.18 stable tree as well.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Based-on-patch-by: David Ahern <david.ahern@oracle.com>
Acked-by: David Ahern <david.ahern@oracle.com>
Cc: David Ahern <dsahern@gmail.com>
Link: http://lkml.kernel.org/r/54EC610C.8000403@intel.com
Cc: stable@vger.kernel.org # v3.18+
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools')
| -rw-r--r-- | tools/perf/util/cloexec.c | 18 |
1 files changed, 15 insertions, 3 deletions
diff --git a/tools/perf/util/cloexec.c b/tools/perf/util/cloexec.c index 47b78b3f0325..6da965bdbc2c 100644 --- a/tools/perf/util/cloexec.c +++ b/tools/perf/util/cloexec.c @@ -25,6 +25,10 @@ static int perf_flag_probe(void) if (cpu < 0) cpu = 0; + /* + * Using -1 for the pid is a workaround to avoid gratuitous jump label + * changes. + */ while (1) { /* check cloexec flag */ fd = sys_perf_event_open(&attr, pid, cpu, -1, @@ -47,16 +51,24 @@ static int perf_flag_probe(void) err, strerror_r(err, sbuf, sizeof(sbuf))); /* not supported, confirm error related to PERF_FLAG_FD_CLOEXEC */ - fd = sys_perf_event_open(&attr, pid, cpu, -1, 0); + while (1) { + fd = sys_perf_event_open(&attr, pid, cpu, -1, 0); + if (fd < 0 && pid == -1 && errno == EACCES) { + pid = 0; + continue; + } + break; + } err = errno; + if (fd >= 0) + close(fd); + if (WARN_ONCE(fd < 0 && err != EBUSY, "perf_event_open(..., 0) failed unexpectedly with error %d (%s)\n", err, strerror_r(err, sbuf, sizeof(sbuf)))) return -1; - close(fd); - return 0; } |