v4.19.13 snapshot.
diff --git a/samples/bpf/tracex6_kern.c b/samples/bpf/tracex6_kern.c
new file mode 100644
index 0000000..46c557a
--- /dev/null
+++ b/samples/bpf/tracex6_kern.c
@@ -0,0 +1,67 @@
+#include <linux/ptrace.h>
+#include <linux/version.h>
+#include <uapi/linux/bpf.h>
+#include "bpf_helpers.h"
+
+struct bpf_map_def SEC("maps") counters = {
+ .type = BPF_MAP_TYPE_PERF_EVENT_ARRAY,
+ .key_size = sizeof(int),
+ .value_size = sizeof(u32),
+ .max_entries = 64,
+};
+struct bpf_map_def SEC("maps") values = {
+ .type = BPF_MAP_TYPE_HASH,
+ .key_size = sizeof(int),
+ .value_size = sizeof(u64),
+ .max_entries = 64,
+};
+struct bpf_map_def SEC("maps") values2 = {
+ .type = BPF_MAP_TYPE_HASH,
+ .key_size = sizeof(int),
+ .value_size = sizeof(struct bpf_perf_event_value),
+ .max_entries = 64,
+};
+
+SEC("kprobe/htab_map_get_next_key")
+int bpf_prog1(struct pt_regs *ctx)
+{
+ u32 key = bpf_get_smp_processor_id();
+ u64 count, *val;
+ s64 error;
+
+ count = bpf_perf_event_read(&counters, key);
+ error = (s64)count;
+ if (error <= -2 && error >= -22)
+ return 0;
+
+ val = bpf_map_lookup_elem(&values, &key);
+ if (val)
+ *val = count;
+ else
+ bpf_map_update_elem(&values, &key, &count, BPF_NOEXIST);
+
+ return 0;
+}
+
+SEC("kprobe/htab_map_lookup_elem")
+int bpf_prog2(struct pt_regs *ctx)
+{
+ u32 key = bpf_get_smp_processor_id();
+ struct bpf_perf_event_value *val, buf;
+ int error;
+
+ error = bpf_perf_event_read_value(&counters, key, &buf, sizeof(buf));
+ if (error)
+ return 0;
+
+ val = bpf_map_lookup_elem(&values2, &key);
+ if (val)
+ *val = buf;
+ else
+ bpf_map_update_elem(&values2, &key, &buf, BPF_NOEXIST);
+
+ return 0;
+}
+
+char _license[] SEC("license") = "GPL";
+u32 _version SEC("version") = LINUX_VERSION_CODE;