From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
To: "Daniel P. Berrange" <berrange@redhat.com>
Cc: qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] Crash with odd chardev setup
Date: Thu, 26 Oct 2017 14:41:29 +0100 [thread overview]
Message-ID: <20171026134128.GA3523@work-vm> (raw)
In-Reply-To: <20171025212302.GE30132@redhat.com>
* Daniel P. Berrange (berrange@redhat.com) wrote:
> On Wed, Oct 25, 2017 at 07:00:14PM +0100, Dr. David Alan Gilbert wrote:
> > Hi Dan,
> > I've got a crash in head (and 2.10) which is a bit of a heisenbug;
> > I can trigger it with:
> >
> > ./qemu-system-x86_64 -netdev tap,id=hostnet0,vhost=on,fd=10 -chardev socket,id=charchannel0,path=/tmp/org.qemu.guest_agent.0,server,nowait -monitor stdio -vnc :0
> >
> > and then 'q' to quit.
>
> Hmm, that doesn't trigger for me on git master at least.
Hmm.
> > Note I'm not doing a redirect in of fd 10.
>
> So it's trying & failing to setup the tap dev, right ?
>
> eg you see this:
>
> # ./x86_64-softmmu/qemu-system-x86_64 -netdev tap,id=hostnet0,vhost=on,fd=10 -chardev socket,id=charchannel0,path=/tmp/org.qemu.guest_agent.0,server,nowait -monitor stdio -vnc :0
> qemu-system-x86_64: -netdev tap,id=hostnet0,vhost=on,fd=10: TUNGETIFF ioctl() failed: Invalid argument
> QEMU 2.10.50 monitor - type 'help' for more information
> (qemu) qemu-system-x86_64: warning: netdev hostnet0 has no peer
>
> (qemu) q
>
>
> Except it crashes at the end ?
Right.
>
>
> > It goes away if I remove either the -netdev or the -chardev option.
> >
> > It doesn't trigger under gdb, but fortunately we get a core:
> >
> > #0 0x000055a226d94a2e in socket_listen_cleanup (fd=<optimized out>, errp=errp@entry=0x7fff3585e8c0)
> > at /root/qemu/util/qemu-sockets.c:1077
> > 1077 if (addr->type == SOCKET_ADDRESS_TYPE_UNIX
> > 1078 && addr->u.q_unix.path) {
> > 1079 if (unlink(addr->u.q_unix.path) < 0 && errno != ENOENT) {
>
> Can you see from the core whether one of those pointers is NULL, or is there
> a complete garbage pointer ?
Gdb showed all the pointers as optimised out I think.
> I wonder if it triggers if you run QEMU under valgrind ?
It does, but it shows:
==29930== Thread 1:
==29930== Invalid read of size 4
==29930== at 0x6F3A2E: socket_listen_cleanup (qemu-sockets.c:1077)
==29930== by 0x6A142A: qio_channel_socket_finalize (channel-socket.c:388)
==29930== by 0x61BA91: object_deinit (object.c:462)
==29930== by 0x61BA91: object_finalize (object.c:476)
==29930== by 0x61BA91: object_unref (object.c:911)
==29930== by 0x6924C8: char_socket_finalize (char-socket.c:805)
==29930== by 0x61BA91: object_deinit (object.c:462)
==29930== by 0x61BA91: object_finalize (object.c:476)
==29930== by 0x61BA91: object_unref (object.c:911)
==29930== by 0x61BACB: object_property_del_all (object.c:413)
==29930== by 0x61BACB: object_finalize (object.c:475)
==29930== by 0x61BACB: object_unref (object.c:911)
==29930== by 0x61AA86: object_property_del_child.isra.7 (object.c:436)
==29930== by 0x3263FE: main (vl.c:4914)
==29930== Address 0x0 is not stack'd, malloc'd or (recently) free'd
so I guess one of the pointers is NULL; I guess I need a few printf's.
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
next prev parent reply other threads:[~2017-10-26 13:41 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-25 18:00 [Qemu-devel] Crash with odd chardev setup Dr. David Alan Gilbert
2017-10-25 21:23 ` Daniel P. Berrange
2017-10-26 13:41 ` Dr. David Alan Gilbert [this message]
2017-10-27 10:31 ` Dr. David Alan Gilbert
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20171026134128.GA3523@work-vm \
--to=dgilbert@redhat.com \
--cc=berrange@redhat.com \
--cc=qemu-devel@nongnu.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.