1 files changed, 68 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/progs/stacktrace_map_skip.c b/tools/testing/selftests/bpf/progs/stacktrace_map_skip.c
new file mode 100644
index 000000000000..2eb297df3dd6
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/stacktrace_map_skip.c
@@ -0,0 +1,68 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <vmlinux.h>
+#include <bpf/bpf_helpers.h>
+
+#define TEST_STACK_DEPTH	2
+#define TEST_MAX_ENTRIES	16384
+
+typedef __u64 stack_trace_t[TEST_STACK_DEPTH];
+
+struct {
+	__uint(type, BPF_MAP_TYPE_STACK_TRACE);
+	__uint(max_entries, TEST_MAX_ENTRIES);
+	__type(key, __u32);
+	__type(value, stack_trace_t);
+} stackmap SEC(".maps");
+
+struct {
+	__uint(type, BPF_MAP_TYPE_HASH);
+	__uint(max_entries, TEST_MAX_ENTRIES);
+	__type(key, __u32);
+	__type(value, __u32);
+} stackid_hmap SEC(".maps");
+
+struct {
+	__uint(type, BPF_MAP_TYPE_ARRAY);
+	__uint(max_entries, TEST_MAX_ENTRIES);
+	__type(key, __u32);
+	__type(value, stack_trace_t);
+} stack_amap SEC(".maps");
+
+int pid = 0;
+int control = 0;
+int failed = 0;
+
+SEC("tracepoint/sched/sched_switch")
+int oncpu(struct trace_event_raw_sched_switch *ctx)
+{
+	__u32 max_len = TEST_STACK_DEPTH * sizeof(__u64);
+	__u32 key = 0, val = 0;
+	__u64 *stack_p;
+
+	if (pid != (bpf_get_current_pid_tgid() >> 32))
+		return 0;
+
+	if (control)
+		return 0;
+
+	/* it should allow skipping whole buffer size entries */
+	key = bpf_get_stackid(ctx, &stackmap, TEST_STACK_DEPTH);
+	if ((int)key >= 0) {
+		/* The size of stackmap and stack_amap should be the same */
+		bpf_map_update_elem(&stackid_hmap, &key, &val, 0);
+		stack_p = bpf_map_lookup_elem(&stack_amap, &key);
+		if (stack_p) {
+			bpf_get_stack(ctx, stack_p, max_len, TEST_STACK_DEPTH);
+			/* it wrongly skipped all the entries and filled zero */
+			if (stack_p[0] == 0)
+				failed = 1;
+		}
+	} else {
+		/* old kernel doesn't support skipping that many entries */
+		failed = 2;
+	}
+
+	return 0;
+}
+
+char _license[] SEC("license") = "GPL";