diff options
Diffstat (limited to 'tools/testing/selftests/bpf/progs/tailcall_fail.c')
-rw-r--r-- | tools/testing/selftests/bpf/progs/tailcall_fail.c | 64 |
1 files changed, 64 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/progs/tailcall_fail.c b/tools/testing/selftests/bpf/progs/tailcall_fail.c new file mode 100644 index 000000000000..bc77921d2bb0 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/tailcall_fail.c @@ -0,0 +1,64 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2024 Meta Platforms, Inc. and affiliates. */ +#include <vmlinux.h> +#include <bpf/bpf_tracing.h> +#include <bpf/bpf_helpers.h> +#include <bpf/bpf_core_read.h> + +#include "bpf_misc.h" +#include "bpf_experimental.h" + +extern void bpf_rcu_read_lock(void) __ksym; +extern void bpf_rcu_read_unlock(void) __ksym; + +#define private(name) SEC(".bss." #name) __hidden __attribute__((aligned(8))) + +private(A) struct bpf_spin_lock lock; + +struct { + __uint(type, BPF_MAP_TYPE_PROG_ARRAY); + __uint(max_entries, 3); + __uint(key_size, sizeof(__u32)); + __uint(value_size, sizeof(__u32)); +} jmp_table SEC(".maps"); + +SEC("?tc") +__failure __msg("function calls are not allowed while holding a lock") +int reject_tail_call_spin_lock(struct __sk_buff *ctx) +{ + bpf_spin_lock(&lock); + bpf_tail_call_static(ctx, &jmp_table, 0); + return 0; +} + +SEC("?tc") +__failure __msg("tail_call cannot be used inside bpf_rcu_read_lock-ed region") +int reject_tail_call_rcu_lock(struct __sk_buff *ctx) +{ + bpf_rcu_read_lock(); + bpf_tail_call_static(ctx, &jmp_table, 0); + bpf_rcu_read_unlock(); + return 0; +} + +SEC("?tc") +__failure __msg("tail_call cannot be used inside bpf_preempt_disable-ed region") +int reject_tail_call_preempt_lock(struct __sk_buff *ctx) +{ + bpf_guard_preempt(); + bpf_tail_call_static(ctx, &jmp_table, 0); + return 0; +} + +SEC("?tc") +__failure __msg("tail_call would lead to reference leak") +int reject_tail_call_ref(struct __sk_buff *ctx) +{ + struct foo { int i; } *p; + + p = bpf_obj_new(typeof(*p)); + bpf_tail_call_static(ctx, &jmp_table, 0); + return 0; +} + +char _license[] SEC("license") = "GPL"; |