Tail calls are deprecated and will be replaced by indirect calls in the future. Reject programs that combine tail calls with stack arguments rather than adding complexity for a deprecated feature. Signed-off-by: Yonghong Song --- kernel/bpf/verifier.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index a363811aec7a..47df3f40a71c 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -5267,14 +5267,23 @@ static int check_max_stack_depth_subprog(struct bpf_verifier_env *env, int idx, * this info will be utilized by JIT so that we will be preserving the * tail call counter throughout bpf2bpf calls combined with tailcalls */ - if (tail_call_reachable) + if (tail_call_reachable) { for (tmp = idx; tmp >= 0; tmp = dinfo[tmp].caller) { if (subprog[tmp].is_exception_cb) { verbose(env, "cannot tail call within exception cb\n"); return -EINVAL; } + if (subprog[tmp].stack_arg_cnt) { + verbose(env, "tail_calls are not allowed in programs with stack args\n"); + return -EINVAL; + } subprog[tmp].tail_call_reachable = true; } + } else if (!idx && subprog[0].has_tail_call && subprog[0].stack_arg_cnt) { + verbose(env, "tail_calls are not allowed in programs with stack args\n"); + return -EINVAL; + } + if (subprog[0].tail_call_reachable) env->prog->aux->tail_call_reachable = true; -- 2.53.0-Meta