1 files changed, 68 insertions, 0 deletions
diff --git a/tools/testing/selftests/damon/debugfs_target_ids_pid_leak.c b/tools/testing/selftests/damon/debugfs_target_ids_pid_leak.c
new file mode 100644
index 000000000000..0cc2eef7d142
--- /dev/null
+++ b/tools/testing/selftests/damon/debugfs_target_ids_pid_leak.c
@@ -0,0 +1,68 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Author: SeongJae Park <sj@kernel.org>
+ */
+
+#define _GNU_SOURCE
+
+#include <fcntl.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <sys/time.h>
+#include <unistd.h>
+
+#define DBGFS_TARGET_IDS "/sys/kernel/debug/damon/target_ids"
+
+static void write_targetid_exit(void)
+{
+	int target_ids_fd = open(DBGFS_TARGET_IDS, O_RDWR);
+	char pid_str[128];
+
+	snprintf(pid_str, sizeof(pid_str), "%d", getpid());
+	write(target_ids_fd, pid_str, sizeof(pid_str));
+	close(target_ids_fd);
+	exit(0);
+}
+
+unsigned long msec_timestamp(void)
+{
+	struct timeval tv;
+
+	gettimeofday(&tv, NULL);
+	return tv.tv_sec * 1000UL + tv.tv_usec / 1000;
+}
+
+int main(int argc, char *argv[])
+{
+	unsigned long start_ms;
+	int time_to_run, nr_forks = 0;
+
+	if (argc != 2) {
+		fprintf(stderr, "Usage: %s <msecs to run>\n", argv[0]);
+		exit(1);
+	}
+	time_to_run = atoi(argv[1]);
+
+	start_ms = msec_timestamp();
+	while (true) {
+		int pid = fork();
+
+		if (pid < 0) {
+			fprintf(stderr, "fork() failed\n");
+			exit(1);
+		}
+		if (pid == 0)
+			write_targetid_exit();
+		wait(NULL);
+		nr_forks++;
+
+		if (msec_timestamp() - start_ms > time_to_run)
+			break;
+	}
+	printf("%d\n", nr_forks);
+	return 0;
+}