From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 09527CA9EAF for ; Fri, 25 Oct 2019 02:46:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D272B21929 for ; Fri, 25 Oct 2019 02:46:44 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="PuXQ0KCn" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390620AbfJYCqo (ORCPT ); Thu, 24 Oct 2019 22:46:44 -0400 Received: from mail-qt1-f193.google.com ([209.85.160.193]:36638 "EHLO mail-qt1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728416AbfJYCqo (ORCPT ); Thu, 24 Oct 2019 22:46:44 -0400 Received: by mail-qt1-f193.google.com with SMTP id d17so1140361qto.3; Thu, 24 Oct 2019 19:46:43 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc:content-transfer-encoding; bh=Uk0O+1Wy0f1d6NdxP+VRsck/NtQSLTDySSKs+mdVowY=; b=PuXQ0KCnl2P4yaeHfvqSabFoaJBb7wgVu0ce9SZksqs7DKyR9UZj6NHadNaRAVfrs6 sdI1NgXt7wn1EC6VEzpOjtZXQzJYp8bN/3+AnzGNBHwtitcKpR0RAkyEaoXfZRciHQyJ VIJgBJyclempLkkOYILP7ilPVscM3zd146VNL69sdN5CHRy8NskNV4CiNIB9LsO3ohJ8 fUdBo8k+XZFNKLlqr8ISVYPTEHAVZ0kr3rRLBMnjHDguXZZQstvXAKx3mMka3DA5CBes f/TrCXdtq4aq80UJAyEndBv2dpUICBwBYekaca+wRBoLfqaXbe6TK2OLiPLHFrazaTN1 C9xg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc:content-transfer-encoding; bh=Uk0O+1Wy0f1d6NdxP+VRsck/NtQSLTDySSKs+mdVowY=; b=QNHi8gA2cEJstmMs6xJgBQu8Loj1m4N9blhkSO0Vp8vv5IBCVS07DBTPGknRxiDi1j vysv0XE+v7tQtFEe5yC+i46qTv/5Ub2H8s2j/TTLIbT0j9LMsILIsQDDcQYDI65XV/nT HsGiKCAqDSYLXLpVc3ypespnC/Q226kGmiN2IVfQEtWxEbXZPNV7TvwzlOocf8pJfGDO Fwov7Lt/IDyikKmHCa9nPmBLUrmDFHgCXYXkU44ki2hNAOcqHdQQPE7b9oYJ6kgm1HF+ 77qUGsC/w0HkEGebTMFh8RTZq3YFjGcFu1hjswXsffciaXgZYnMMplLaSkUflmoXpT+z /JBg== X-Gm-Message-State: APjAAAXz9LdOGOPEMiMzbHKQtAoFiXS0jbKnTilALCthshSUk1UncjiW ZdXeody86B4MMeY2sU+n3bj+NjVelKrF7XvgvCE= X-Google-Smtp-Source: APXvYqzZFlki7XvE0PhidpQ6wNk28XXjDGbkhyCAkn+YCRu/7+ZaMJy37cwTVv+GgZmDMSbrU2cH3JsyjF0BYqpTJTU= X-Received: by 2002:ac8:66d9:: with SMTP id m25mr886913qtp.117.1571971603014; Thu, 24 Oct 2019 19:46:43 -0700 (PDT) MIME-Version: 1.0 References: <157192269744.234778.11792009511322809519.stgit@toke.dk> <157192269854.234778.6284587028332090249.stgit@toke.dk> In-Reply-To: <157192269854.234778.6284587028332090249.stgit@toke.dk> From: Andrii Nakryiko Date: Thu, 24 Oct 2019 19:46:31 -0700 Message-ID: Subject: Re: [PATCH bpf-next v2 1/4] libbpf: Fix error handling in bpf_map__reuse_fd() To: =?UTF-8?B?VG9rZSBIw7hpbGFuZC1Kw7hyZ2Vuc2Vu?= Cc: Daniel Borkmann , Alexei Starovoitov , Martin KaFai Lau , Song Liu , Yonghong Song , Jesper Dangaard Brouer , David Miller , Networking , bpf Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On Thu, Oct 24, 2019 at 6:11 AM Toke H=C3=B8iland-J=C3=B8rgensen wrote: > > From: Toke H=C3=B8iland-J=C3=B8rgensen > > bpf_map__reuse_fd() was calling close() in the error path before returnin= g > an error value based on errno. However, close can change errno, so that c= an > lead to potentially misleading error messages. Instead, explicitly store > errno in the err variable before each goto. > > Signed-off-by: Toke H=C3=B8iland-J=C3=B8rgensen > --- Thanks! Acked-by: Andrii Nakryiko > tools/lib/bpf/libbpf.c | 14 ++++++++++---- > 1 file changed, 10 insertions(+), 4 deletions(-) > > diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c > index cccfd9355134..a2a7d074ac48 100644 > --- a/tools/lib/bpf/libbpf.c > +++ b/tools/lib/bpf/libbpf.c > @@ -1918,16 +1918,22 @@ int bpf_map__reuse_fd(struct bpf_map *map, int fd= ) > return -errno; > > new_fd =3D open("/", O_RDONLY | O_CLOEXEC); > - if (new_fd < 0) > + if (new_fd < 0) { > + err =3D -errno; > goto err_free_new_name; > + } > > new_fd =3D dup3(fd, new_fd, O_CLOEXEC); > - if (new_fd < 0) > + if (new_fd < 0) { > + err =3D -errno; > goto err_close_new_fd; > + } > > err =3D zclose(map->fd); > - if (err) > + if (err) { > + err =3D -errno; > goto err_close_new_fd; > + } > free(map->name); > > map->fd =3D new_fd; > @@ -1946,7 +1952,7 @@ int bpf_map__reuse_fd(struct bpf_map *map, int fd) > close(new_fd); > err_free_new_name: > free(new_name); > - return -errno; > + return err; > } > > int bpf_map__resize(struct bpf_map *map, __u32 max_entries) >