Commit-ID: 48536c9195ae8c2a00fd8f400bac72ab613feaab Gitweb: http://git.kernel.org/tip/48536c9195ae8c2a00fd8f400bac72ab613feaab Author: Adrian Hunter <adrian.hun...@intel.com> AuthorDate: Tue, 24 Feb 2015 13:20:59 +0200 Committer: Arnaldo Carvalho de Melo <a...@redhat.com> CommitDate: Wed, 25 Feb 2015 16:40:13 -0300
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.hun...@intel.com> Based-on-patch-by: David Ahern <david.ah...@oracle.com> Acked-by: David Ahern <david.ah...@oracle.com> Cc: David Ahern <dsah...@gmail.com> Link: http://lkml.kernel.org/r/54ec610c.8000...@intel.com Cc: sta...@vger.kernel.org # v3.18+ Signed-off-by: Arnaldo Carvalho de Melo <a...@redhat.com> --- tools/perf/util/cloexec.c | 18 +++++++++++++++--- 1 file changed, 15 insertions(+), 3 deletions(-) diff --git a/tools/perf/util/cloexec.c b/tools/perf/util/cloexec.c index 47b78b3..6da965b 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; } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
