Re: [PATCH bpf v1 3/3] selftests/bpf: Avoid a clobbering of errno

[Jakub Kicinski]

On Wed, 15 May 2019 15:47:28 +0200, Krzesimir Nowak wrote:
> Save errno right after bpf_prog_test_run returns, so we later check
> the error code actually set by bpf_prog_test_run, not by some libcap
> function.
> 
> Cc: Jakub Kicinski <jakub.kicin...@netronome.com>
> Fixes: 5a8d5209ac022 ("selftests: bpf: add trivial JSET tests")

This commit (of mine) just moved this code into a helper, the bug is
older:

Fixes: 832c6f2c29ec ("bpf: test make sure to run unpriv test cases in 
test_verifier")

> Signed-off-by: Krzesimir Nowak <krzesi...@kinvolk.io>
> ---
>  tools/testing/selftests/bpf/test_verifier.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/tools/testing/selftests/bpf/test_verifier.c 
> b/tools/testing/selftests/bpf/test_verifier.c
> index bf0da03f593b..514e17246396 100644
> --- a/tools/testing/selftests/bpf/test_verifier.c
> +++ b/tools/testing/selftests/bpf/test_verifier.c
> @@ -818,15 +818,17 @@ static int do_prog_test_run(int fd_prog, bool unpriv, 
> uint32_t expected_val,
>       __u32 size_tmp = sizeof(tmp);
>       uint32_t retval;
>       int err;
> +     int saved_errno;
>  
>       if (unpriv)
>               set_admin(true);
>       err = bpf_prog_test_run(fd_prog, 1, data, size_data,
>                               tmp, &size_tmp, &retval, NULL);
> +     saved_errno = errno;
>       if (unpriv)
>               set_admin(false);
>       if (err) {
> -             switch (errno) {
> +             switch (saved_errno) {
>               case 524/*ENOTSUPP*/:
>                       printf("Did not run the program (not supported) ");
>                       return 0;