[PATCHv2 bpf-next] selftests/bpf: Fix d_path test

Jiri Olsa
2023-08-31T14:11:09Z

Recent commit [1] broken d_path test, because now filp_close is not called
directly from sys_close, but eventually later when the file is finally
released.

As suggested by Hou Tao we don't need to re-hook the bpf program, but just
instead we can use sys_close_range to trigger filp_close synchronously.

[1] 021a160abf62 ("fs: use __fput_sync in close(2)")
Suggested-by: Hou Tao <houtao@huaweicloud.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
.../testing/selftests/bpf/prog_tests/d_path.c | 19 ++++++++++++++++++-
1 file changed, 18 insertions(+), 1 deletion(-)

v2: call close_range through syscall call [Hou Tao]

diff --git a/tools/testing/selftests/bpf/prog_tests/d_path.c b/tools/testing/selftests/bpf/prog_tests/d_path.c
index 911345c526e6..ccc768592e66 100644
--- a/tools/testing/selftests/bpf/prog_tests/d_path.c
+++ b/tools/testing/selftests/bpf/prog_tests/d_path.c
@@ -12,6 +12,17 @@
#include "test_d_path_check_rdonly_mem.skel.h"
#include "test_d_path_check_types.skel.h"

+/* sys_close_range is not around for long time, so let's
+ * make sure we can call it on systems with older glibc
+ */
+#ifndef __NR_close_range
+#ifdef __alpha__
+#define __NR_close_range 546
+#else
+#define __NR_close_range 436
+#endif
+#endif
+
static int duration;

static struct {
@@ -90,7 +101,11 @@ static int trigger_fstat_events(pid_t pid)
fstat(indicatorfd, &fileStat);

out_close:
- /* triggers filp_close */
+ /* sys_close no longer triggers filp_close, but we can
+ * call sys_close_range instead which still does
+ */
+#define close(fd) syscall(__NR_close_range, fd, fd, 0)
+
close(pipefd[0]);
close(pipefd[1]);
close(sockfd);
@@ -98,6 +113,8 @@ static int trigger_fstat_events(pid_t pid)
close(devfd);
close(localfd);
close(indicatorfd);
+
+#undef close
return ret;
}

--
2.41.0