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authorAdrian Hunter <adrian.hunter@intel.com>2015-02-24 13:20:59 +0200
committerArnaldo Carvalho de Melo <acme@redhat.com>2015-02-25 16:40:13 -0300
commit48536c9195ae8c2a00fd8f400bac72ab613feaab (patch)
tree59621cfff58dca6939d0cb780e3857d416bad2b7 /tools
parentperf tools: Fix pthread_attr_setaffinity_np build error (diff)
downloadlinux-dev-48536c9195ae8c2a00fd8f400bac72ab613feaab.tar.xz
linux-dev-48536c9195ae8c2a00fd8f400bac72ab613feaab.zip
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.c18
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;
}