1 files changed, 98 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/progs/test_ringbuf_overwrite.c b/tools/testing/selftests/bpf/progs/test_ringbuf_overwrite.c
new file mode 100644
index 000000000000..ff4aa67ddacc
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_ringbuf_overwrite.c
@@ -0,0 +1,98 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (C) 2025. Huawei Technologies Co., Ltd */
+
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+#include "bpf_misc.h"
+
+char _license[] SEC("license") = "GPL";
+
+struct {
+	__uint(type, BPF_MAP_TYPE_RINGBUF);
+	__uint(map_flags, BPF_F_RB_OVERWRITE);
+} ringbuf SEC(".maps");
+
+int pid;
+
+const volatile unsigned long LEN1;
+const volatile unsigned long LEN2;
+const volatile unsigned long LEN3;
+const volatile unsigned long LEN4;
+const volatile unsigned long LEN5;
+
+long reserve1_fail = 0;
+long reserve2_fail = 0;
+long reserve3_fail = 0;
+long reserve4_fail = 0;
+long reserve5_fail = 0;
+
+unsigned long avail_data = 0;
+unsigned long ring_size = 0;
+unsigned long cons_pos = 0;
+unsigned long prod_pos = 0;
+unsigned long over_pos = 0;
+
+SEC("fentry/" SYS_PREFIX "sys_getpgid")
+int test_overwrite_ringbuf(void *ctx)
+{
+	char *rec1, *rec2, *rec3, *rec4, *rec5;
+	int cur_pid = bpf_get_current_pid_tgid() >> 32;
+
+	if (cur_pid != pid)
+		return 0;
+
+	rec1 = bpf_ringbuf_reserve(&ringbuf, LEN1, 0);
+	if (!rec1) {
+		reserve1_fail = 1;
+		return 0;
+	}
+
+	rec2 = bpf_ringbuf_reserve(&ringbuf, LEN2, 0);
+	if (!rec2) {
+		bpf_ringbuf_discard(rec1, 0);
+		reserve2_fail = 1;
+		return 0;
+	}
+
+	rec3 = bpf_ringbuf_reserve(&ringbuf, LEN3, 0);
+	/* expect failure */
+	if (!rec3) {
+		reserve3_fail = 1;
+	} else {
+		bpf_ringbuf_discard(rec1, 0);
+		bpf_ringbuf_discard(rec2, 0);
+		bpf_ringbuf_discard(rec3, 0);
+		return 0;
+	}
+
+	rec4 = bpf_ringbuf_reserve(&ringbuf, LEN4, 0);
+	if (!rec4) {
+		reserve4_fail = 1;
+		bpf_ringbuf_discard(rec1, 0);
+		bpf_ringbuf_discard(rec2, 0);
+		return 0;
+	}
+
+	bpf_ringbuf_submit(rec1, 0);
+	bpf_ringbuf_submit(rec2, 0);
+	bpf_ringbuf_submit(rec4, 0);
+
+	rec5 = bpf_ringbuf_reserve(&ringbuf, LEN5, 0);
+	if (!rec5) {
+		reserve5_fail = 1;
+		return 0;
+	}
+
+	for (int i = 0; i < LEN3; i++)
+		rec5[i] = 0xdd;
+
+	bpf_ringbuf_submit(rec5, 0);
+
+	ring_size = bpf_ringbuf_query(&ringbuf, BPF_RB_RING_SIZE);
+	avail_data = bpf_ringbuf_query(&ringbuf, BPF_RB_AVAIL_DATA);
+	cons_pos = bpf_ringbuf_query(&ringbuf, BPF_RB_CONS_POS);
+	prod_pos = bpf_ringbuf_query(&ringbuf, BPF_RB_PROD_POS);
+	over_pos = bpf_ringbuf_query(&ringbuf, BPF_RB_OVERWRITE_POS);
+
+	return 0;
+}