// 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; }