On 2021/05/29 4:46, Daniel Borkmann wrote:
On 5/28/21 11:07 AM, Yu Kuai wrote:
use libbpf_get_error() to check the return value of bpf_program__attach().
Reported-by: Hulk Robot hulkci@huawei.com Signed-off-by: Yu Kuai yukuai3@huawei.com
tools/testing/selftests/bpf/benchs/bench_rename.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tools/testing/selftests/bpf/benchs/bench_rename.c b/tools/testing/selftests/bpf/benchs/bench_rename.c index c7ec114eca56..b7d4a1d74fca 100644 --- a/tools/testing/selftests/bpf/benchs/bench_rename.c +++ b/tools/testing/selftests/bpf/benchs/bench_rename.c @@ -65,7 +65,7 @@ static void attach_bpf(struct bpf_program *prog) struct bpf_link *link; link = bpf_program__attach(prog); - if (!link) { + if (libbpf_get_error(link)) { fprintf(stderr, "failed to attach program!\n"); exit(1); }
Could you explain the rationale of this patch? bad2e478af3b ("selftests/bpf: Turn on libbpf 1.0 mode and fix all IS_ERR checks") explains: 'Fix all the explicit IS_ERR checks that now will be broken because libbpf returns NULL on error (and sets errno).' So the !link check looks totally reasonable to me. Converting to libbpf_get_error() is not wrong in itself, but given you don't make any use of the err code, there is also no point in this diff here.
Hi,
I was thinking that bpf_program__attach() can return error code theoretically(for example -ESRCH), and such case need to be handled.
Thanks, Yu Kuai
Thanks, Daniel .