selftests/bpf: Fix d_path test

Recent commit [1] broke 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] 021a160 ("fs: use __fput_sync in close(2)")

Suggested-by: Hou Tao <[email protected]>
Signed-off-by: Jiri Olsa <[email protected]>
Signed-off-by: Daniel Borkmann <[email protected]>
Link: https://lore.kernel.org/bpf/[email protected]

Author: olsajiri

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 {
@@ -90,14 +101,20 @@ 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);
 	close(procfd);
 	close(devfd);
 	close(localfd);
 	close(indicatorfd);
+
+#undef close
 	return ret;
 }