[PATCH] bpf: Add env_type_is_resolved() in front of env_stack_push() in btf_resolve()

From: jiasheng
Date: Thu Sep 02 2021 - 02:37:49 EST


We have found that in the complied files env_stack_push()
appear more than 10 times, and under at least 90% circumstances
that env_type_is_resolved() and env_stack_push() appear in pairs.
For example, they appear together in the btf_modifier_resolve()
of the file complie from 'kernel/bpf/btf.c'.
But we have found that in the btf_resolve(), there is only
env_stack_push() instead of the pair.
Therefore, we consider that the env_type_is_resolved()
might be forgotten.

Signed-off-by: jiasheng <jiasheng@xxxxxxxxxxx>
---
kernel/bpf/btf.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index f982a9f0..454c249 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -4002,7 +4002,8 @@ static int btf_resolve(struct btf_verifier_env *env,
int err = 0;

env->resolve_mode = RESOLVE_TBD;
- env_stack_push(env, t, type_id);
+ if (env_type_is_resolved(env, type_id))
+ env_stack_push(env, t, type_id);
while (!err && (v = env_stack_peak(env))) {
env->log_type_id = v->type_id;
err = btf_type_ops(v->t)->resolve(env, v);
--
2.7.4