From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:44976) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dcSbV-0001e3-4A for qemu-devel@nongnu.org; Tue, 01 Aug 2017 04:32:38 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dcSbR-0000kE-6h for qemu-devel@nongnu.org; Tue, 01 Aug 2017 04:32:37 -0400 Received: from mx1.redhat.com ([209.132.183.28]:40006) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1dcSbR-0000jz-0e for qemu-devel@nongnu.org; Tue, 01 Aug 2017 04:32:33 -0400 Date: Tue, 1 Aug 2017 09:32:20 +0100 From: "Daniel P. Berrange" Message-ID: <20170801083220.GB12670@redhat.com> Reply-To: "Daniel P. Berrange" References: <1501229198-30588-1-git-send-email-peterx@redhat.com> <1501229198-30588-4-git-send-email-peterx@redhat.com> <20170731165339.GD2122@work-vm> <20170801022519.GB15697@pxdev.xzpeter.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20170801022519.GB15697@pxdev.xzpeter.org> Subject: Re: [Qemu-devel] [RFC 03/29] io: fix qio_channel_socket_accept err handling List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Peter Xu Cc: "Dr. David Alan Gilbert" , qemu-devel@nongnu.org, Laurent Vivier , Alexey Perevalov , Juan Quintela , Andrea Arcangeli , stefanha@redhat.com On Tue, Aug 01, 2017 at 10:25:19AM +0800, Peter Xu wrote: > On Mon, Jul 31, 2017 at 05:53:39PM +0100, Dr. David Alan Gilbert wrote: > > * Peter Xu (peterx@redhat.com) wrote: > > > When accept failed, we should setup errp with the reason. More > > > importantly, the caller may assume errp be non-NULL when error happens, > > > and not setting the errp may crash QEMU. > > > > > > Signed-off-by: Peter Xu > > > --- > > > io/channel-socket.c | 1 + > > > 1 file changed, 1 insertion(+) > > > > > > diff --git a/io/channel-socket.c b/io/channel-socket.c > > > index 53386b7..7bc308e 100644 > > > --- a/io/channel-socket.c > > > +++ b/io/channel-socket.c > > > @@ -344,6 +344,7 @@ qio_channel_socket_accept(QIOChannelSocket *ioc, > > > if (errno == EINTR) { > > > goto retry; > > > } > > > + error_setg_errno(errp, errno, "Unable to accept connection"); > > > goto error; > > > > OK, but this code actually has a bigger problem as well: > > > > the original is: > > > > cioc->fd = qemu_accept(ioc->fd, (struct sockaddr *)&cioc->remoteAddr, > > &cioc->remoteAddrLen); > > if (cioc->fd < 0) { > > trace_qio_channel_socket_accept_fail(ioc); > > if (errno == EINTR) { > > goto retry; > > } > > goto error; > > } > > > > Stefan confirmed that trace_ doesn't preserve errno; so the if > > following it is wrong. It needs to preserve errno. > > Ah... If so, not sure whether we can do the reservation in trace codes > in general? > > For this one, I can just move the trace_*() below the errno check. > After all, if EINTR is got, it's not really a fail, so imho we should > not trace it with "accept fail". Agreed, we just need to move the trace below the if. Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|