From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:50241) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dcSxV-0007Zn-I1 for qemu-devel@nongnu.org; Tue, 01 Aug 2017 04:55:22 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dcSxR-0000Ew-Hc for qemu-devel@nongnu.org; Tue, 01 Aug 2017 04:55:21 -0400 Received: from mx1.redhat.com ([209.132.183.28]:53636) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1dcSxR-0000Ei-8C for qemu-devel@nongnu.org; Tue, 01 Aug 2017 04:55:17 -0400 Date: Tue, 1 Aug 2017 09:55:08 +0100 From: "Dr. David Alan Gilbert" Message-ID: <20170801085507.GC2079@work-vm> 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> <20170801083220.GB12670@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170801083220.GB12670@redhat.com> 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: "Daniel P. Berrange" Cc: Peter Xu , qemu-devel@nongnu.org, Laurent Vivier , Alexey Perevalov , Juan Quintela , Andrea Arcangeli , stefanha@redhat.com * Daniel P. Berrange (berrange@redhat.com) wrote: > 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. Peter: Can you split this as a separate patch and it seems OK to try and put this in 2.10 since it's a strict bug fix. Dave > > 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 :| -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK