# Re: \[PATCH net\] bpf: uninitialized variables in test code

- From: Alexei Starovoitov \<hidden\>
- Date: 2018-12-01 10:08:58 
- List: netdev
- Page: https://ratatoskr.run/netdev/2018/12/11116998
- Thread: https://ratatoskr.run/netdev/2018/11/11116715/t.md

```text
On Thu, Nov 29, 2018 at 01:27:03PM +0300, Dan Carpenter wrote:
> Smatch complains that if bpf_test_run() fails with -ENOMEM at the
> begining then the "duration" is uninitialized.  We then copy the
> unintialized variables to the user inside the bpf_test_finish()
> function.  The functions require CAP_SYS_ADMIN so it's not really an
> information leak.
> 
> Fixes: 1cf1cae963c2 ("bpf: introduce BPF_PROG_TEST_RUN command")
> Signed-off-by: Dan Carpenter <redacted>

That is incorrect fixes tag.
It should be pointing to commit f42ee093be29 ("bpf/test_run: support cgroup local storage")

bpf_test_run() can only return the value that bpf program returned.
It cannot return -ENOMEM.
That code needs to be refactored.
I think the proper way for bpf_test_run() would be to return 0 or -ENOMEM
and store bpf's retval into extra pointer.
Proper checks need to be added in the callers (bpf_prog_test_run_skb, etc).

Dan, can you do such refactoring or you want to punt back to Roman ?
```