bpf: fix max call depth check
fix off by one error in max call depth check
and add a test
Fixes: f4d7e40a5b71 ("bpf: introduce function calls (verification)")
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 738e919..52ad60b 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -2126,9 +2126,9 @@ static int check_func_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
struct bpf_func_state *caller, *callee;
int i, subprog, target_insn;
- if (state->curframe >= MAX_CALL_FRAMES) {
+ if (state->curframe + 1 >= MAX_CALL_FRAMES) {
verbose(env, "the call stack of %d frames is too deep\n",
- state->curframe);
+ state->curframe + 2);
return -E2BIG;
}