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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2823CC433F5 for ; Fri, 12 Nov 2021 08:35:34 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 7736B60F41 for ; Fri, 12 Nov 2021 08:35:33 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 7736B60F41 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=nongnu.org Received: from localhost ([::1]:46458 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mlS20-0006l8-G9 for qemu-devel@archiver.kernel.org; Fri, 12 Nov 2021 03:35:32 -0500 Received: from eggs.gnu.org ([209.51.188.92]:34784) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mlS0l-0005JE-Sl; Fri, 12 Nov 2021 03:34:15 -0500 Received: from [2a00:1450:4864:20::529] (port=37696 helo=mail-ed1-x529.google.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1mlS0k-0003Mo-5s; Fri, 12 Nov 2021 03:34:15 -0500 Received: by mail-ed1-x529.google.com with SMTP id f8so34923005edy.4; Fri, 12 Nov 2021 00:34:10 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=L3nIHK4dZymNrDEdGJJgKuKTK5CWB8GpctHS/f2nfDA=; b=o4PuLFTChSHeWfCxE84RdsVOQkP7z0zQB3CpmSwzaM9xAsJroIWfmpJ4kFNlpeUU2a bsQ6FBqjUR4SJ4IJqCcL4jWvAN4/8xTo1Wj6v/+l77IQmBapIsEangLJ5dn7imPOVP69 7IbAzJSkI2INt/1BHyLgquxgMtOHec2qDMe2ppVrZxz6P1a9oQB4alyYd9uKoelqjpw0 vA9+wgLyMJEA97IpQ9Gws+IG0RlfbMKNhScC4dQ9c9lm2uL6d1JZsZeBO6Bq9cq99I9b Vm59TC3i4ZuP5EsjBKpRB406soXiaOmqREkMm0wuMp6QAZ+Gb9aUsTk9PkRtCg2ncrak OnIg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=L3nIHK4dZymNrDEdGJJgKuKTK5CWB8GpctHS/f2nfDA=; b=vuYZMLbaNbtVUYxGKcfmK+R+T4mcR84bFR3qWh0HEV2lwlhbbr/p8E8sqjItAA5byc /qSibjJ1DyDXjy5Jml7Gsh/sSKOfendDuUfaHhARtTsgfn2W2oDMcmMedvNEbITQLF4A EIRaurOLaCA3tNKm6obq5Nt1FoXZDAcyn8XAlG8IZRLWvuXsC5gL3Hd+jSMbersWKiaU +XBH8gAd8wJt9gKgH6S/32Cc3mdsHSKyjAN7qKJ3jdtS1m2cdvFH8+7UA1ysPLZXHppP viw1/pCxHndgkbLPrcjsVJk1QY+LTsW0aveBonWH6p261Kk8wpQV897k7YuWtstm2E5E zy3Q== X-Gm-Message-State: AOAM532ek4HfVYZtHLgMxYXOSG3GARu4pRlq9FbDXenxjM1m4/cTYxhI PbEgA+hifPfCYGYxBN6eBaiTsDwbDyJSiv7NEm96BtpV X-Google-Smtp-Source: ABdhPJxdrfbVB4nv6y/gGd+13UL5RUQnInWlsD9xJU3CdUIXNYwjelfvBbsI8s7Po7hTbHnQxjStHsQ40o3fsP4S84Q= X-Received: by 2002:a5d:44d1:: with SMTP id z17mr16917974wrr.143.1636705708443; Fri, 12 Nov 2021 00:28:28 -0800 (PST) MIME-Version: 1.0 References: <20211111153354.18807-1-rvkagan@yandex-team.ru> <20211111153354.18807-4-rvkagan@yandex-team.ru> In-Reply-To: <20211111153354.18807-4-rvkagan@yandex-team.ru> From: =?UTF-8?B?TWFyYy1BbmRyw6kgTHVyZWF1?= Date: Fri, 12 Nov 2021 12:28:16 +0400 Message-ID: Subject: Re: [PATCH 03/10] chardev/char-socket: tcp_chr_sync_read: don't clobber errno To: Roman Kagan Content-Type: multipart/alternative; boundary="0000000000005a8c4f05d0933e12" X-Host-Lookup-Failed: Reverse DNS lookup failed for 2a00:1450:4864:20::529 (failed) Received-SPF: pass client-ip=2a00:1450:4864:20::529; envelope-from=marcandre.lureau@gmail.com; helo=mail-ed1-x529.google.com X-Spam_score_int: -12 X-Spam_score: -1.3 X-Spam_bar: - X-Spam_report: (-1.3 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, FREEMAIL_FROM=0.001, HTML_MESSAGE=0.001, PDS_HP_HELO_NORDNS=0.001, RCVD_IN_DNSWL_NONE=-0.0001, RDNS_NONE=0.793, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , "open list:Block layer core" , "Michael S. Tsirkin" , QEMU , Raphael Norwitz , Hanna Reitz , yc-core@yandex-team.ru, Paolo Bonzini Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" --0000000000005a8c4f05d0933e12 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Thu, Nov 11, 2021 at 7:36 PM Roman Kagan wrote: > After the return from tcp_chr_recv, tcp_chr_sync_read calls into a > function which eventually makes a system call and may clobber errno. > > Make a copy of errno right after tcp_chr_recv and restore the errno on > return from tcp_chr_sync_read. > > Signed-off-by: Roman Kagan > Reviewed-by: Marc-Andr=C3=A9 Lureau --- > chardev/char-socket.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/chardev/char-socket.c b/chardev/char-socket.c > index 90054ce58c..cf7f2ba65a 100644 > --- a/chardev/char-socket.c > +++ b/chardev/char-socket.c > @@ -581,6 +581,7 @@ static int tcp_chr_sync_read(Chardev *chr, const > uint8_t *buf, int len) > { > SocketChardev *s =3D SOCKET_CHARDEV(chr); > int size; > + int saved_errno; > > if (s->state !=3D TCP_CHARDEV_STATE_CONNECTED) { > return 0; > @@ -588,6 +589,7 @@ static int tcp_chr_sync_read(Chardev *chr, const > uint8_t *buf, int len) > > qio_channel_set_blocking(s->ioc, true, NULL); > size =3D tcp_chr_recv(chr, (void *) buf, len); > + saved_errno =3D errno; > if (s->state !=3D TCP_CHARDEV_STATE_DISCONNECTED) { > qio_channel_set_blocking(s->ioc, false, NULL); > } > @@ -596,6 +598,7 @@ static int tcp_chr_sync_read(Chardev *chr, const > uint8_t *buf, int len) > tcp_chr_disconnect(chr); > } > > + errno =3D saved_errno; > return size; > } > > -- > 2.33.1 > > > --=20 Marc-Andr=C3=A9 Lureau --0000000000005a8c4f05d0933e12 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable


=
On Thu, Nov 11, 2021 at 7:36 PM Roman= Kagan <rvkagan@yandex-team.ru= > wrote:
= After the return from tcp_chr_recv, tcp_chr_sync_read calls into a
function which eventually makes a system call and may clobber errno.

Make a copy of errno right after tcp_chr_recv and restore the errno on
return from tcp_chr_sync_read.

Signed-off-by: Roman Kagan <rvkagan@yandex-team.ru>

Reviewed-by: Marc-Andr=C3=A9 Lureau <marcandre.lureau@redhat.com>

---
=C2=A0chardev/char-socket.c | 3 +++
=C2=A01 file changed, 3 insertions(+)

diff --git a/chardev/char-socket.c b/chardev/char-socket.c
index 90054ce58c..cf7f2ba65a 100644
--- a/chardev/char-socket.c
+++ b/chardev/char-socket.c
@@ -581,6 +581,7 @@ static int tcp_chr_sync_read(Chardev *chr, const uint8_= t *buf, int len)
=C2=A0{
=C2=A0 =C2=A0 =C2=A0SocketChardev *s =3D SOCKET_CHARDEV(chr);
=C2=A0 =C2=A0 =C2=A0int size;
+=C2=A0 =C2=A0 int saved_errno;

=C2=A0 =C2=A0 =C2=A0if (s->state !=3D TCP_CHARDEV_STATE_CONNECTED) {
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0return 0;
@@ -588,6 +589,7 @@ static int tcp_chr_sync_read(Chardev *chr, const uint8_= t *buf, int len)

=C2=A0 =C2=A0 =C2=A0qio_channel_set_blocking(s->ioc, true, NULL);
=C2=A0 =C2=A0 =C2=A0size =3D tcp_chr_recv(chr, (void *) buf, len);
+=C2=A0 =C2=A0 saved_errno =3D errno;
=C2=A0 =C2=A0 =C2=A0if (s->state !=3D TCP_CHARDEV_STATE_DISCONNECTED) {<= br> =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0qio_channel_set_blocking(s->ioc, false= , NULL);
=C2=A0 =C2=A0 =C2=A0}
@@ -596,6 +598,7 @@ static int tcp_chr_sync_read(Chardev *chr, const uint8_= t *buf, int len)
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0tcp_chr_disconnect(chr);
=C2=A0 =C2=A0 =C2=A0}

+=C2=A0 =C2=A0 errno =3D saved_errno;
=C2=A0 =C2=A0 =C2=A0return size;
=C2=A0}

--
2.33.1




--
Marc-Andr=C3=A9 Lureau
--0000000000005a8c4f05d0933e12--