On Fri, 17 Jun 2011 12:17:36 +0530 Amit Shah <amit.s...@redhat.com> wrote:
> On (Thu) 16 Jun 2011 [13:38:49], Luiz Capitulino wrote: > > If I start qemu with: > > > > # qemu -hda disks/test.img -enable-kvm -m 1G -snapshot \ > > -device virtio-serial \ > > -chardev socket,host=localhost,port=1234,server,nowait,id=foo \ > > -device virtserialport,chardev=foo,name=org.qemu.guest_agent > > > > I get a segfault when booting a Fedora 14 guest. The backtrace says: > > > > Program terminated with signal 11, Segmentation fault. > > #0 0x0000000000420850 in handle_control_message (vser=0x3732bd0, > > buf=0x2c173e0, len=8) at > > /home/lcapitulino/src/qmp-unstable/hw/virtio-serial-bus.c:335 > > 335 info = DO_UPCAST(VirtIOSerialPortInfo, qdev, port->dev.info); > > Strange, I've not seen it so far in my testing (neither in the daily > test runs of the virtio-serial testsuite). > > > I've also bisected this and git points out to commit: > > > > commit a15bb0d6a981de749452a5180fc8084d625671da > > Author: Markus Armbruster <arm...@redhat.com> > > Date: Wed May 25 14:21:13 2011 +0200 > > > > virtio-serial: Drop redundant VirtIOSerialPort member info > > > > I think what's happening is that the device is not initialized on a > > VIRTIO_CONSOLE_DEVICE_READY event. Moving the DO_UPCAST() call to > > the other events fixes the problem to me. > > > > Signed-off-by: Luiz Capitulino <lcapitul...@redhat.com> > > --- > > hw/virtio-serial-bus.c | 4 ++-- > > 1 files changed, 2 insertions(+), 2 deletions(-) > > > > diff --git a/hw/virtio-serial-bus.c b/hw/virtio-serial-bus.c > > index 9a12104..579f676 100644 > > --- a/hw/virtio-serial-bus.c > > +++ b/hw/virtio-serial-bus.c > > @@ -332,8 +332,6 @@ static void handle_control_message(VirtIOSerial *vser, > > void *buf, size_t len) > > if (!port && cpkt.event != VIRTIO_CONSOLE_DEVICE_READY) > > return; > > > > - info = DO_UPCAST(VirtIOSerialPortInfo, qdev, port->dev.info); > > - > > Ah - this missed the !port check. It should be possible to do this in > a 'if (port)' block instead of replicating in the individual case > statements. > > Thanks for the debugging and patch; please update with the above and > I'll apply it to the virtio-serial tree. What about moving the VIRTIO_CONSOLE_DEVICE_READY handling out of the switch, like the patch below? This way the function is divided in a way that related events are handled together. I'll implement your first suggestion if you don't like this... diff --git a/hw/virtio-serial-bus.c b/hw/virtio-serial-bus.c index 579f676..5f96245 100644 --- a/hw/virtio-serial-bus.c +++ b/hw/virtio-serial-bus.c @@ -325,19 +325,12 @@ static void handle_control_message(VirtIOSerial *vser, void *buf, size_t len) return; } - cpkt.event = lduw_p(&gcpkt->event); cpkt.value = lduw_p(&gcpkt->value); - - port = find_port_by_id(vser, ldl_p(&gcpkt->id)); - if (!port && cpkt.event != VIRTIO_CONSOLE_DEVICE_READY) - return; - - switch(cpkt.event) { - case VIRTIO_CONSOLE_DEVICE_READY: + cpkt.event = lduw_p(&gcpkt->event); + if (cpkt.event == VIRTIO_CONSOLE_DEVICE_READY) { if (!cpkt.value) { - error_report("virtio-serial-bus: Guest failure in adding device %s\n", - vser->bus.qbus.name); - break; + error_report("virtio-serial-bus: Guest failure in adding device %s\n", vser->bus.qbus.name); + return; } /* * The device is up, we can now tell the device about all the @@ -346,8 +339,13 @@ static void handle_control_message(VirtIOSerial *vser, void *buf, size_t len) QTAILQ_FOREACH(port, &vser->ports, next) { send_control_event(port, VIRTIO_CONSOLE_PORT_ADD, 1); } - break; + return; + } + port = find_port_by_id(vser, ldl_p(&gcpkt->id)); + assert(port != NULL); + + switch(cpkt.event) { case VIRTIO_CONSOLE_PORT_READY: if (!cpkt.value) { error_report("virtio-serial-bus: Guest failure in adding port %u for device %s\n",