[PATCH bpf-next] bpf: btf: don't log ignored BTF mismatches

[Connor O'Brien]

Enabling CONFIG_MODULE_ALLOW_BTF_MISMATCH is an indication that BTF
mismatches are expected and module loading should proceed
anyway. Logging with pr_warn() on every one of these "benign"
mismatches creates unnecessary noise when many such modules are
loaded. Instead, limit logging to the case where a BTF mismatch
actually prevents a module form loading.

Signed-off-by: Connor O'Brien <connoro@xxxxxxxxxx>
---
 kernel/bpf/btf.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index 5579ff3a5b54..406370487413 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -7190,11 +7190,12 @@ static int btf_module_notify(struct notifier_block *nb, unsigned long op,
 		}
 		btf = btf_parse_module(mod->name, mod->btf_data, mod->btf_data_size);
 		if (IS_ERR(btf)) {
-			pr_warn("failed to validate module [%s] BTF: %ld\n",
-				mod->name, PTR_ERR(btf));
 			kfree(btf_mod);
-			if (!IS_ENABLED(CONFIG_MODULE_ALLOW_BTF_MISMATCH))
+			if (!IS_ENABLED(CONFIG_MODULE_ALLOW_BTF_MISMATCH)) {
+				pr_warn("failed to validate module [%s] BTF: %ld\n",
+					mod->name, PTR_ERR(btf));
 				err = PTR_ERR(btf);
+			}
 			goto out;
 		}
 		err = btf_alloc_id(btf);
-- 
2.38.1.431.g37b22c650d-goog