diff --git a/src/tests/kernel/libroot/posix/Jamfile b/src/tests/kernel/libroot/posix/Jamfile
index 48c8dcd091..717d23a5c1 100644
--- a/src/tests/kernel/libroot/posix/Jamfile
+++ b/src/tests/kernel/libroot/posix/Jamfile
@@ -4,6 +4,12 @@ UsePrivateHeaders syslog_daemon ;
 
 SimpleTest SyslogTest
 	: SyslogTest.cpp syslog.cpp
+	: libroot.so
+	;
+
+SimpleTest flock_test
+	: flock_test.cpp
+	: libroot.so
 	;
 
 # Tell Jam where to find these sources
diff --git a/src/tests/kernel/libroot/posix/flock_test.cpp b/src/tests/kernel/libroot/posix/flock_test.cpp
new file mode 100644
index 0000000000..e5d71ce021
--- /dev/null
+++ b/src/tests/kernel/libroot/posix/flock_test.cpp
@@ -0,0 +1,169 @@
+/*
+ * Copyright 2005, Axel Dörfler, axeld@pinc-software.de.
+ * Distributed under the terms of the MIT License.
+ */
+
+
+#include <OS.h>
+
+#include <fcntl.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <string.h>
+#include <errno.h>
+
+
+bool gDone = false;
+
+
+static int32
+try_to_lock(void *_fd)
+{
+	int fd = (int)_fd;
+
+	struct flock flock = {
+		F_RDLCK,	// shared lock
+		SEEK_SET,
+		200,
+		0,			// until the end of the file
+		0
+	};
+
+	if (fcntl(fd, F_SETLK, &flock) == 0) {
+		fprintf(stderr, "a. Could lock file!\n");
+		return -1;
+	} else
+		puts("test a passed.");
+
+	gDone = true;
+
+	// wait for lock to become free
+
+	if (fcntl(fd, F_SETLKW, &flock) == -1) {
+		fprintf(stderr, "b. Could not lock file: %s\n", strerror(errno));
+		return -1;
+	} else
+		puts("test b passed.");
+
+	flock.l_type = F_UNLCK;
+
+	if (fcntl(fd, F_SETLK, &flock) == -1) {
+		fprintf(stderr, "c. Could not unlock file: %s\n", strerror(errno));
+		return -1;
+	} else
+		puts("test c passed.");
+
+	return 0;
+}
+
+
+int 
+main(int argc, char **argv)
+{
+	int fd = open("/bin/sh", O_RDONLY);
+	if (fd < 0) {
+		fprintf(stderr, "could not open file: %s\n", strerror(errno));
+		return -1;
+	}
+
+	struct flock flock = {
+		F_WRLCK,	// exclusive lock
+		SEEK_SET,	// lock whole file
+		0,
+		0,
+		0
+	};
+
+	if (fcntl(fd, F_SETLK, &flock) == 0) {
+		fprintf(stderr, "0. Could lock file exclusively without write access!\n");
+		return -1;
+	} else
+		puts("test 0 passed.");
+
+	flock.l_type = F_RDLCK;
+		// shared locks should be allowed
+
+	if (fcntl(fd, F_SETLK, &flock) == -1) {
+		fprintf(stderr, "1. Could not lock file: %s\n", strerror(errno));
+		return -1;
+	} else
+		puts("test 1 passed.");
+
+	close(fd);
+
+	fd = open("/bin/sh", O_RDWR);
+	if (fd < 0) {
+		fprintf(stderr, "could not open file: %s\n", strerror(errno));
+		return -1;
+	}
+
+	flock.l_type = F_WRLCK;
+	flock.l_start = 100;
+	flock.l_len = 42;
+
+	if (fcntl(fd, F_SETLK, &flock) == -1) {
+		fprintf(stderr, "2. Could not lock file: %s\n", strerror(errno));
+		return -1;
+	} else
+		puts("test 2 passed.");
+
+	flock.l_start = 200;
+
+	if (fcntl(fd, F_SETLK, &flock) == -1) {
+		fprintf(stderr, "3. Could not lock file: %s\n", strerror(errno));
+		return -1;
+	} else
+		puts("test 3 passed.");
+
+	flock.l_start = 80;
+
+	if (fcntl(fd, F_SETLK, &flock) == 0) {
+		fprintf(stderr, "4. Could lock file exclusively on locked region!\n");
+		return -1;
+	} else
+		puts("test 4 passed.");
+
+	flock.l_type = F_UNLCK;
+	flock.l_start = 100;
+
+	if (fcntl(fd, F_SETLK, &flock) == -1) {
+		fprintf(stderr, "5. Could not unlock file: %s\n", strerror(errno));
+		return -1;
+	} else
+		puts("test 5 passed.");
+
+	flock.l_type = F_WRLCK;
+	flock.l_start = 80;
+
+	if (fcntl(fd, F_SETLK, &flock) == -1) {
+		fprintf(stderr, "6. Could not lock file: %s\n", strerror(errno));
+		return -1;
+	} else
+		puts("test 6 passed.");
+
+	thread_id thread = spawn_thread(try_to_lock, "try", B_NORMAL_PRIORITY, (void *)fd);
+	if (thread < B_OK) {
+		fprintf(stderr, "Could not spawn thread: %s\n", strerror(thread));
+		return -1;
+	}
+	resume_thread(thread);
+
+	while (!gDone) {
+		snooze(100000); // 0.1s
+	}
+
+	flock.l_type = F_UNLCK;
+	flock.l_start = 200;
+
+	if (fcntl(fd, F_SETLK, &flock) == -1) {
+		fprintf(stderr, "7. Could not unlock file: %s\n", strerror(errno));
+		return -1;
+	} else
+		puts("test 7 passed.");
+
+	status_t returnCode;
+	wait_for_thread(thread, &returnCode);
+
+	close(fd);
+	return 0;
+}