commit 10d274e880eb208ec6a76261a9f8f8155020f771
author Alexei Starovoitov <ast@kernel.org> Thu Aug 22 22:52:12 2019 -0700
committer Daniel Borkmann <daniel@iogearbox.net> Wed Aug 28 00:30:11 2019 +0200
tree 5188b50b171df8b2d1528ec60d2ec69cb2e775d5
parent 0bb52b0dfc88a155688f492aba8e686147600278

bpf: introduce verifier internal test flag

Introduce BPF_F_TEST_STATE_FREQ flag to stress test parentage chain
and state pruning.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

kernel/bpf/verifier.c

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 10c0ff9..f340cfe 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -7222,7 +7222,7 @@ static int is_state_visited(struct bpf_verifier_env *env, int insn_idx)
 	struct bpf_verifier_state_list *sl, **pprev;
 	struct bpf_verifier_state *cur = env->cur_state, *new;
 	int i, j, err, states_cnt = 0;
-	bool add_new_state = false;
+	bool add_new_state = env->test_state_freq ? true : false;
 
 	cur->last_insn_idx = env->prev_insn_idx;
 	if (!env->insn_aux_data[insn_idx].prune_point)
@@ -9262,6 +9262,9 @@ int bpf_check(struct bpf_prog **prog, union bpf_attr *attr,
 
 	env->allow_ptr_leaks = is_priv;
 
+	if (is_priv)
+		env->test_state_freq = attr->prog_flags & BPF_F_TEST_STATE_FREQ;
+
 	ret = replace_map_fd_with_map_ptr(env);
 	if (ret < 0)
 		goto skip_full_check;