On Tue, May 28, 2019 at 6:14 PM Andrii Nakryiko <andriin@xxxxxx> wrote:
>
> pr_warning ultimately may call into user-provided callback function,
> which can clobber errno value, so we need to save it before that.
>
> Signed-off-by: Andrii Nakryiko <andriin@xxxxxx>
Acked-by: Song Liu <songliubraving@xxxxxx>
> ---
> tools/lib/bpf/libbpf.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
> index 05a73223e524..7b80b9ae8a1f 100644
> --- a/tools/lib/bpf/libbpf.c
> +++ b/tools/lib/bpf/libbpf.c
> @@ -565,12 +565,12 @@ static int bpf_object__elf_init(struct bpf_object *obj)
> } else {
> obj->efile.fd = open(obj->path, O_RDONLY);
> if (obj->efile.fd < 0) {
> - char errmsg[STRERR_BUFSIZE];
> - char *cp = libbpf_strerror_r(errno, errmsg,
> - sizeof(errmsg));
> + char errmsg[STRERR_BUFSIZE], *cp;
>
> + err = -errno;
> + cp = libbpf_strerror_r(err, errmsg, sizeof(errmsg));
> pr_warning("failed to open %s: %s\n", obj->path, cp);
> - return -errno;
> + return err;
> }
>
> obj->efile.elf = elf_begin(obj->efile.fd,
> --
> 2.17.1
>
