From d2e4d08b3e02deb2d5824b17283c63c1354b7696 Mon Sep 17 00:00:00 2001 From: Luiz Capitulino Date: Fri, 17 Jun 2011 15:58:08 -0300 Subject: [PATCH] virtio-serial: Fix segfault on guest boot 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); What's happening is VIRTIO_CONSOLE_DEVICE_READY is a message for the whole device, not for an individual port. So port is NULL. This bug was introduced by commit a15bb0d6a981de749452a5180fc8084d625671da. This commit fixes that by making the port returned by find_port_by_id() be used only by the VIRTIO_CONSOLE_PORT_READY and VIRTIO_CONSOLE_PORT_OPEN messages. Signed-off-by: Luiz Capitulino Reviewed-by: Markus Armbruster Signed-off-by: Amit Shah --- hw/virtio-serial-bus.c | 24 ++++++++++++++---------- 1 file changed, 14 insertions(+), 10 deletions(-) diff --git a/hw/virtio-serial-bus.c b/hw/virtio-serial-bus.c index 9a12104982..7cedf1855d 100644 --- a/hw/virtio-serial-bus.c +++ b/hw/virtio-serial-bus.c @@ -328,18 +328,11 @@ static void handle_control_message(VirtIOSerial *vser, void *buf, size_t len) 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; - - info = DO_UPCAST(VirtIOSerialPortInfo, qdev, port->dev.info); - - switch(cpkt.event) { - case VIRTIO_CONSOLE_DEVICE_READY: + 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; + return; } /* * The device is up, we can now tell the device about all the @@ -348,8 +341,19 @@ 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)); + if (!port) { + error_report("virtio-serial-bus: Unexpected port id %u for device %s\n", + ldl_p(&gcpkt->id), vser->bus.qbus.name); + return; + } + + info = DO_UPCAST(VirtIOSerialPortInfo, qdev, port->dev.info); + + 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",