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Re: [Qemu-devel] [RFC 03/29] io: fix qio_channel_socket_accept err handl
From: |
Peter Xu |
Subject: |
Re: [Qemu-devel] [RFC 03/29] io: fix qio_channel_socket_accept err handling |
Date: |
Tue, 1 Aug 2017 10:25:19 +0800 |
User-agent: |
Mutt/1.5.24 (2015-08-30) |
On Mon, Jul 31, 2017 at 05:53:39PM +0100, Dr. David Alan Gilbert wrote:
> * Peter Xu (address@hidden) 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 <address@hidden>
> > ---
> > 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".
>
> (Again this patch can go on it's own)
Yes. For these patches, I intentionally put them at the beginning of
the series (for easier picking up standalone). Do you (or Juan?) want
me to repost these patches separately?
--
Peter Xu
- [Qemu-devel] [RFC 00/29] Migration: postcopy failure recovery, Peter Xu, 2017/07/28
- [Qemu-devel] [RFC 01/29] migration: fix incorrect postcopy recved_bitmap, Peter Xu, 2017/07/28
- [Qemu-devel] [RFC 02/29] migration: fix comment disorder in RAMState, Peter Xu, 2017/07/28
- [Qemu-devel] [RFC 03/29] io: fix qio_channel_socket_accept err handling, Peter Xu, 2017/07/28
- [Qemu-devel] [RFC 04/29] bitmap: introduce bitmap_invert(), Peter Xu, 2017/07/28
- [Qemu-devel] [RFC 05/29] bitmap: introduce bitmap_count_one(), Peter Xu, 2017/07/28
- [Qemu-devel] [RFC 06/29] migration: dump str in migrate_set_state trace, Peter Xu, 2017/07/28
- [Qemu-devel] [RFC 08/29] migration: reuse mis->userfault_quit_fd, Peter Xu, 2017/07/28
- [Qemu-devel] [RFC 07/29] migration: better error handling with QEMUFile, Peter Xu, 2017/07/28