[PATCH AUTOSEL 4.20 275/304] perf python: Do not force closing original perf descriptor in evlist.get_pollfd()

Sasha Levin
2019-01-28T15:57:41Z

From: Jiri Olsa <jolsa@kernel.org>

[ Upstream commit a389aece97938966616ce0336466b98b0351ef10 ]

Ondřej reported that when compiled with python3, the python extension
regresses in evlist.get_pollfd function behaviour.

The evlist.get_pollfd function creates file objects from evlist's fds
and returns them in a list. The python3 version also sets them to 'close
the original descriptor' when the object dies (is closed), by passing
True via the 'closefd' arg in the PyFile_FromFd call.

The python's closefd doc says:

If closefd is False, the underlying file descriptor will be kept open
when the file is closed.

That's why the following line in python3 closes all evlist fds:

evlist.get_pollfd()

the returned list is immediately destroyed and that takes down the
original events fds.

Passing closefd as False to PyFile_FromFd to fix this.

Reported-by: Ondřej Lysoněk <olysonek@redhat.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jaroslav Škarvada <jskarvad@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Fixes: 66dfdff03d19 ("perf tools: Add Python 3 support")
Link: http://lkml.kernel.org/r/20181226112121.5285-1-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
tools/perf/util/python.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/tools/perf/util/python.c b/tools/perf/util/python.c
index 50150dfc0cdf..4dd8fd05a260 100644
--- a/tools/perf/util/python.c
+++ b/tools/perf/util/python.c
@@ -939,7 +939,8 @@ static PyObject *pyrf_evlist__get_pollfd(struct pyrf_evlist *pevlist,

file = PyFile_FromFile(fp, "perf", "r", NULL);
#else
- file = PyFile_FromFd(evlist->pollfd.entries[i].fd, "perf", "r", -1, NULL, NULL, NULL, 1);
+ file = PyFile_FromFd(evlist->pollfd.entries[i].fd, "perf", "r", -1,
+ NULL, NULL, NULL, 0);
#endif
if (file == NULL)
goto free_list;
--
2.19.1