Re: [PATCH] btf: move kern_type_id to goto cand_cache_unlock

[Pu Lehui]

On 2025/2/20 13:50, Ethan Carter Edwards wrote:
In most code paths variable move_kern_type_id remains uninitialized upon
return. By moving it to the goto, it is initialized in these code paths.
As well as others. Caught by Coverity.
Closes: 
https://scan5.scan.coverity.com/#/project-view/63874/10063?selectedIssue=1595567
Fixes: e2b3c4ff5d183d ("bpf: add __arg_trusted global func arg tag")
Signed-off-by: Ethan Carter Edwards <et...@ethancedwards.com>
---
  kernel/bpf/btf.c | 2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index 
9de6acddd479b4f5e32a5e6ba43cf369de4cee29..8c82ced7da299ad1ad769024fe097898c269013b
 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -7496,9 +7496,9 @@ static int btf_get_ptr_to_btf_id(struct bpf_verifier_log 
*log, int arg_idx,
                err = -EOPNOTSUPP;
                goto cand_cache_unlock;
        }
-       kern_type_id = cc->cands[0].id;
  
  cand_cache_unlock:
+       kern_type_id = cc->cands[0].id;

Hi, for goto's branches, it will always `return err`, no need to make 
this move.

        mutex_unlock(&cand_cache_mutex);
        if (err)
                return err;

---
base-commit: 87a132e73910e8689902aed7f2fc229d6908383b
change-id: 20250220-bpf-uninit-3323a4426da9

Best regards,