diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
index dcd850546d522dff78341d90ea9a991c01e1ab4d..fe98fb226e6e1af21dae6feb5684ebc30faffb50 100644
--- a/samples/bpf/Makefile
+++ b/samples/bpf/Makefile
@@ -9,6 +9,7 @@ hostprogs-y += sockex2
 hostprogs-y += tracex1
 hostprogs-y += tracex2
 hostprogs-y += tracex3
+hostprogs-y += tracex4
 
 test_verifier-objs := test_verifier.o libbpf.o
 test_maps-objs := test_maps.o libbpf.o
@@ -18,6 +19,7 @@ sockex2-objs := bpf_load.o libbpf.o sockex2_user.o
 tracex1-objs := bpf_load.o libbpf.o tracex1_user.o
 tracex2-objs := bpf_load.o libbpf.o tracex2_user.o
 tracex3-objs := bpf_load.o libbpf.o tracex3_user.o
+tracex4-objs := bpf_load.o libbpf.o tracex4_user.o
 
 # Tell kbuild to always build the programs
 always := $(hostprogs-y)
@@ -26,6 +28,7 @@ always += sockex2_kern.o
 always += tracex1_kern.o
 always += tracex2_kern.o
 always += tracex3_kern.o
+always += tracex4_kern.o
 
 HOSTCFLAGS += -I$(objtree)/usr/include
 
@@ -35,6 +38,7 @@ HOSTLOADLIBES_sockex2 += -lelf
 HOSTLOADLIBES_tracex1 += -lelf
 HOSTLOADLIBES_tracex2 += -lelf
 HOSTLOADLIBES_tracex3 += -lelf
+HOSTLOADLIBES_tracex4 += -lelf -lrt
 
 # point this to your LLVM backend with bpf support
 LLC=$(srctree)/tools/bpf/llvm/bld/Debug+Asserts/bin/llc
diff --git a/samples/bpf/tracex4_kern.c b/samples/bpf/tracex4_kern.c
new file mode 100644
index 0000000000000000000000000000000000000000..126b80512228aa6493c8332e75933ab5852acab1
--- /dev/null
+++ b/samples/bpf/tracex4_kern.c
@@ -0,0 +1,54 @@
+/* Copyright (c) 2015 PLUMgrid, http://plumgrid.com
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of version 2 of the GNU General Public
+ * License as published by the Free Software Foundation.
+ */
+#include <linux/ptrace.h>
+#include <linux/version.h>
+#include <uapi/linux/bpf.h>
+#include "bpf_helpers.h"
+
+struct pair {
+	u64 val;
+	u64 ip;
+};
+
+struct bpf_map_def SEC("maps") my_map = {
+	.type = BPF_MAP_TYPE_HASH,
+	.key_size = sizeof(long),
+	.value_size = sizeof(struct pair),
+	.max_entries = 1000000,
+};
+
+/* kprobe is NOT a stable ABI. If kernel internals change this bpf+kprobe
+ * example will no longer be meaningful
+ */
+SEC("kprobe/kmem_cache_free")
+int bpf_prog1(struct pt_regs *ctx)
+{
+	long ptr = ctx->si;
+
+	bpf_map_delete_elem(&my_map, &ptr);
+	return 0;
+}
+
+SEC("kretprobe/kmem_cache_alloc_node")
+int bpf_prog2(struct pt_regs *ctx)
+{
+	long ptr = ctx->ax;
+	long ip = 0;
+
+	/* get ip address of kmem_cache_alloc_node() caller */
+	bpf_probe_read(&ip, sizeof(ip), (void *)(ctx->bp + sizeof(ip)));
+
+	struct pair v = {
+		.val = bpf_ktime_get_ns(),
+		.ip = ip,
+	};
+
+	bpf_map_update_elem(&my_map, &ptr, &v, BPF_ANY);
+	return 0;
+}
+char _license[] SEC("license") = "GPL";
+u32 _version SEC("version") = LINUX_VERSION_CODE;
diff --git a/samples/bpf/tracex4_user.c b/samples/bpf/tracex4_user.c
new file mode 100644
index 0000000000000000000000000000000000000000..bc4a3bdea6ed4cbceed4478899702b8ee04dd8eb
--- /dev/null
+++ b/samples/bpf/tracex4_user.c
@@ -0,0 +1,69 @@
+/* Copyright (c) 2015 PLUMgrid, http://plumgrid.com
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of version 2 of the GNU General Public
+ * License as published by the Free Software Foundation.
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include <signal.h>
+#include <unistd.h>
+#include <stdbool.h>
+#include <string.h>
+#include <time.h>
+#include <linux/bpf.h>
+#include "libbpf.h"
+#include "bpf_load.h"
+
+struct pair {
+	long long val;
+	__u64 ip;
+};
+
+static __u64 time_get_ns(void)
+{
+	struct timespec ts;
+
+	clock_gettime(CLOCK_MONOTONIC, &ts);
+	return ts.tv_sec * 1000000000ull + ts.tv_nsec;
+}
+
+static void print_old_objects(int fd)
+{
+	long long val = time_get_ns();
+	__u64 key, next_key;
+	struct pair v;
+
+	key = write(1, "\e[1;1H\e[2J", 12); /* clear screen */
+
+	key = -1;
+	while (bpf_get_next_key(map_fd[0], &key, &next_key) == 0) {
+		bpf_lookup_elem(map_fd[0], &next_key, &v);
+		key = next_key;
+		if (val - v.val < 1000000000ll)
+			/* object was allocated more then 1 sec ago */
+			continue;
+		printf("obj 0x%llx is %2lldsec old was allocated at ip %llx\n",
+		       next_key, (val - v.val) / 1000000000ll, v.ip);
+	}
+}
+
+int main(int ac, char **argv)
+{
+	char filename[256];
+	int i;
+
+	snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
+
+	if (load_bpf_file(filename)) {
+		printf("%s", bpf_log_buf);
+		return 1;
+	}
+
+	for (i = 0; ; i++) {
+		print_old_objects(map_fd[1]);
+		sleep(1);
+	}
+
+	return 0;
+}