diff --git a/samples/bpf/tracex4_kern.c b/samples/bpf/tracex4_kern.c
new file mode 100644
index 0000000..126b805
--- /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;