zhenwei pi
2019-May-05 01:53 UTC
[PATCH] virtio_console: remove vq buf while unpluging port
A bug can be easily reproduced:
Host# cat guest-agent.xml
<channel type="unix">
<source mode="bind"
path="/var/lib/libvirt/qemu/stretch.agent"/>
<target type="virtio" name="org.qemu.guest_agent.0"
state="connected"/>
</channel>
Host# virsh attach-device instance guest-agent.xml
Host# virsh detach-device instance guest-agent.xml
Host# virsh attach-device instance guest-agent.xml
and guest report: virtio-ports vport0p1: Error allocating inbufs
The reason is that the port is unplugged and the vq buf still remained.
So, fix two cases in this patch:
1, fix memory leak with attach-device/detach-device.
2, fix logic bug with attach-device/detach-device/attach-device.
Signed-off-by: zhenwei pi <pizhenwei at bytedance.com>
---
drivers/char/virtio_console.c | 21 +++++++++++++++------
1 file changed, 15 insertions(+), 6 deletions(-)
diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
index fbeb719..f6e37f4 100644
--- a/drivers/char/virtio_console.c
+++ b/drivers/char/virtio_console.c
@@ -251,6 +251,7 @@ struct port {
/* This is the very early arch-specified put chars function. */
static int (*early_put_chars)(u32, const char *, int);
+static void remove_vq(struct virtqueue *vq);
static struct port *find_port_by_vtermno(u32 vtermno)
{
@@ -1550,6 +1551,9 @@ static void unplug_port(struct port *port)
}
remove_port_data(port);
+ spin_lock_irq(&port->inbuf_lock);
+ remove_vq(port->in_vq);
+ spin_unlock_irq(&port->inbuf_lock);
/*
* We should just assume the device itself has gone off --
@@ -1945,17 +1949,22 @@ static const struct file_operations portdev_fops = {
.owner = THIS_MODULE,
};
+static void remove_vq(struct virtqueue *vq)
+{
+ struct port_buffer *buf;
+
+ flush_bufs(vq, true);
+ while ((buf = virtqueue_detach_unused_buf(vq)))
+ free_buf(buf, true);
+}
+
static void remove_vqs(struct ports_device *portdev)
{
struct virtqueue *vq;
- virtio_device_for_each_vq(portdev->vdev, vq) {
- struct port_buffer *buf;
+ virtio_device_for_each_vq(portdev->vdev, vq)
+ remove_vq(vq);
- flush_bufs(vq, true);
- while ((buf = virtqueue_detach_unused_buf(vq)))
- free_buf(buf, true);
- }
portdev->vdev->config->del_vqs(portdev->vdev);
kfree(portdev->in_vqs);
kfree(portdev->out_vqs);
--
2.7.4