[PATCH 5.4 081/102] kselftests: cgroup: Avoid the reuse of fd after it is deallocated

[Greg Kroah-Hartman]

From: Hewenliang <hewenliang4@xxxxxxxxxx>

[ Upstream commit d671fa6393d6788fc65555d4643b71cb3a361f36 ]

It is necessary to set fd to -1 when inotify_add_watch() fails in
cg_prepare_for_wait. Otherwise the fd which has been closed in
cg_prepare_for_wait may be misused in other functions such as
cg_enter_and_wait_for_frozen and cg_freeze_wait.

Fixes: 5313bfe425c8 ("selftests: cgroup: add freezer controller self-tests")
Signed-off-by: Hewenliang <hewenliang4@xxxxxxxxxx>
Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 tools/testing/selftests/cgroup/test_freezer.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/tools/testing/selftests/cgroup/test_freezer.c b/tools/testing/selftests/cgroup/test_freezer.c
index 0fc1b6d4b0f9c..62a27ab3c2f3e 100644
--- a/tools/testing/selftests/cgroup/test_freezer.c
+++ b/tools/testing/selftests/cgroup/test_freezer.c
@@ -72,6 +72,7 @@ static int cg_prepare_for_wait(const char *cgroup)
 	if (ret == -1) {
 		debug("Error: inotify_add_watch() failed\n");
 		close(fd);
+		fd = -1;
 	}
 
 	return fd;
-- 
2.20.1