From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Adrian Hunter , David Ahern , David Ahern , Arnaldo Carvalho de Melo Subject: [PATCH 3.18 137/151] perf tools: Fix probing for PERF_FLAG_FD_CLOEXEC flag Date: Tue, 3 Mar 2015 22:14:31 -0800 Message-Id: <20150304055519.895078057@linuxfoundation.org> In-Reply-To: <20150304055457.084276421@linuxfoundation.org> References: <20150304055457.084276421@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Adrian Hunter commit 48536c9195ae8c2a00fd8f400bac72ab613feaab upstream. 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 Based-on-patch-by: David Ahern Acked-by: David Ahern Cc: David Ahern Link: http://lkml.kernel.org/r/54EC610C.8000403@intel.com Signed-off-by: Arnaldo Carvalho de Melo Signed-off-by: Greg Kroah-Hartman --- tools/perf/util/cloexec.c | 18 +++++++++++++++--- 1 file changed, 15 insertions(+), 3 deletions(-) --- 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; }