diff --git a/ctdb/tests/src/test_mutex_raw.c b/ctdb/tests/src/test_mutex_raw.c
new file mode 100644
index 00000000000..8e3cae34c89
--- /dev/null
+++ b/ctdb/tests/src/test_mutex_raw.c
@@ -0,0 +1,261 @@
+/*
+   Robust mutex test
+
+   Copyright (C) Amitay Isaacs  2016
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, see <http://www.gnu.org/licenses/>.
+*/
+
+/*
+ * Run this test as follows:
+ *
+ * 1. Running all processes at normal priority
+ *
+ *  $ while true ; do ./bin/test_mutex_raw /tmp/foo 10 0 ; done
+ *
+ * 2. Running all processes at real-time priority
+ *
+ *  # while true ; do ./bin/test_mutex_raw /tmp/foo 10 1 ; done
+ *
+ * The test will block after few iterations.  At this time none of the 
+ * child processes is holding the mutex.
+ *
+ * To check which process is holding a lock:
+ *
+ *  $ ./bin/test_mutex_raw /tmp/foo debug
+ *
+ *  If no pid is printed, then no process is holding the mutex.
+ */
+
+#include <stdio.h>
+#include <unistd.h>
+#include <inttypes.h>
+#include <sys/types.h>
+#include <sys/fcntl.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/wait.h>
+#include <sched.h>
+#include <sys/mman.h>
+#include <pthread.h>
+#include <errno.h>
+#include <stdbool.h>
+
+int pthread_mutex_consistent_np(pthread_mutex_t *);
+
+static void set_realtime(void)
+{
+	struct sched_param p;
+	int ret;
+
+	p.sched_priority = 1;
+
+	ret = sched_setscheduler(0, SCHED_FIFO, &p);
+	if (ret == -1) {
+		fprintf(stderr, "Failed to set scheduler to SCHED_FIFO\n");
+	}
+}
+
+static void high_priority(void)
+{
+	int ret;
+
+	ret = nice(-20);
+	if (ret == -1) {
+		fprintf(stderr, "Failed to set high priority\n");
+	}
+}
+
+static void run_child(const char *filename)
+{
+	pthread_mutex_t *mutex;
+	void *addr;
+	int ret, fd;
+
+	fd = open(filename, O_RDWR, 0600);
+	if (fd == -1) {
+		exit(1);
+	}
+
+	addr = mmap(NULL, sizeof(pthread_mutex_t), PROT_READ|PROT_WRITE,
+		    MAP_SHARED|MAP_FILE, fd, 0);
+	if (addr == NULL) {
+		exit(2);
+	}
+
+	mutex = (pthread_mutex_t *)addr;
+
+again:
+	ret = pthread_mutex_lock(mutex);
+	if (ret == EOWNERDEAD) {
+		ret = pthread_mutex_consistent_np(mutex);
+	} else if (ret == EAGAIN) {
+		goto again;
+	}
+	if (ret != 0) {
+		fprintf(stderr, "pid %u lock failed, ret=%d\n", getpid(), ret);
+		exit(3);
+	}
+
+	fprintf(stderr, "pid %u locked\n", getpid());
+	kill(getpid(), SIGKILL);
+}
+
+#define PRIO_NORMAL	0
+#define PRIO_REALTIME	1
+#define PRIO_NICE_20	2
+
+int main(int argc, const char **argv)
+{
+	pthread_mutexattr_t ma;
+	pthread_mutex_t *mutex;
+	int fd, ret, i;
+	pid_t pid;
+	void *addr;
+	int num_children;
+	int priority = PRIO_NORMAL;
+
+	if (argc < 3 || argc > 4) {
+		fprintf(stderr, "Usage: %s <file> <n> [0|1|2]\n", argv[0]);
+		fprintf(stderr, "       %s <file> debug\n", argv[0]);
+		exit(1);
+	}
+
+	if (argc == 4) {
+		priority = atoi(argv[3]);
+	}
+
+	if (priority == PRIO_REALTIME) {
+		set_realtime();
+	} else if (priority == PRIO_NICE_20) {
+		high_priority();
+	}
+
+	fd = open(argv[1], O_CREAT|O_RDWR, 0600);
+	if (fd == -1) {
+		fprintf(stderr, "open failed\n");
+		exit(1);
+	}
+
+	ret = lseek(fd, 0, SEEK_SET);
+	if (ret != 0) {
+		fprintf(stderr, "lseek failed\n");
+		exit(1);
+	}
+
+	ret = ftruncate(fd, sizeof(pthread_mutex_t));
+	if (ret != 0) {
+		fprintf(stderr, "ftruncate failed\n");
+		exit(1);
+	}
+
+	addr = mmap(NULL, sizeof(pthread_mutex_t), PROT_READ|PROT_WRITE,
+		    MAP_SHARED|MAP_FILE, fd, 0);
+	if (addr == NULL) {
+		fprintf(stderr, "mmap failed\n");
+		exit(1);
+	}
+
+	mutex = (pthread_mutex_t *)addr;
+
+	if (strcmp(argv[2], "debug") == 0) {
+		ret = pthread_mutex_trylock(mutex);
+		if (ret == EOWNERDEAD) {
+			ret = pthread_mutex_consistent_np(mutex);
+			if (ret == 0) {
+				pthread_mutex_unlock(mutex);
+			}
+		} else if (ret == EBUSY) {
+			printf("pid=%u\n", mutex->__data.__owner);
+		} else if (ret == 0) {
+			pthread_mutex_unlock(mutex);
+		}
+		exit(0);
+	}
+
+	ret = pthread_mutexattr_init(&ma);
+	if (ret != 0) {
+		fprintf(stderr, "pthread_mutexattr_init failed\n");
+		exit(1);
+	}
+
+	ret = pthread_mutexattr_settype(&ma, PTHREAD_MUTEX_ERRORCHECK);
+	if (ret != 0) {
+		fprintf(stderr, "pthread_mutexattr_settype failed\n");
+		exit(1);
+	}
+
+	ret = pthread_mutexattr_setpshared(&ma, PTHREAD_PROCESS_SHARED);
+	if (ret != 0) {
+		fprintf(stderr, "pthread_mutexattr_setpshared failed\n");
+		exit(1);
+	}
+
+	ret = pthread_mutexattr_setrobust(&ma, PTHREAD_MUTEX_ROBUST);
+	if (ret != 0) {
+		fprintf(stderr, "pthread_mutexattr_setrobust failed\n");
+		exit(1);
+	}
+
+	ret = pthread_mutex_init(mutex, &ma);
+	if (ret != 0) {
+		fprintf(stderr, "pthread_mutex_init failed\n");
+		exit(1);
+	}
+
+	ret = pthread_mutex_lock(mutex);
+	if (ret != 0) {
+		fprintf(stderr, "pthread_mutex_lock failed\n");
+		exit(1);
+	}
+
+	setpgid(0, 0);
+
+	fprintf(stderr, "Creating children\n");
+	num_children = atoi(argv[2]);
+
+	for (i=0; i<num_children; i++) {
+		pid = fork();
+		if (pid < 0) {
+			fprintf(stderr, "fork() failed\n");
+			exit(1);
+		}
+		if (pid == 0) {
+			close(fd);
+			run_child(argv[1]);
+			exit(1);
+		}
+	}
+
+	fprintf(stderr, "Waiting for children\n");
+
+	ret = pthread_mutex_unlock(mutex);
+	if (ret != 0) {
+		fprintf(stderr, "pthread_mutex_unlock failed\n");
+		exit(1);
+	}
+
+	for (i=0; i<num_children; i++) {
+		int status;
+
+		pid = waitpid(-1, &status, 0);
+		if (pid <= 0) {
+			fprintf(stderr, "waitpid() failed\n");
+		}
+	}
+
+	close(fd);
+	unlink(argv[1]);
+	exit(0);
+}
diff --git a/ctdb/wscript b/ctdb/wscript
index 6f633e27609..b9a3072801e 100644
--- a/ctdb/wscript
+++ b/ctdb/wscript
@@ -830,6 +830,11 @@ def build(bld):
                               ib_deps,
                          install_path='${CTDB_TEST_LIBEXECDIR}')
 
+    bld.SAMBA_BINARY('test_mutex_raw',
+                     source='tests/src/test_mutex_raw.c',
+                     deps='pthread',
+                     install_path='${CTDB_TEST_LIBEXECDIR}')
+
     test_subdirs = [
         'complex',
         'cunit',