@@ -132,6 +132,7 @@ struct ports_device {
/* To protect the vq operations for the control channel */
spinlock_t c_ivq_lock;
+ spinlock_t c_ovq_lock;
/* The current config space is stored here */
struct virtio_console_config config;
@@ -457,11 +458,13 @@ static ssize_t __send_control_msg(struct ports_device *portdev, u32 port_id,
vq = portdev->c_ovq;
sg_init_one(sg, &cpkt, sizeof(cpkt));
+ spin_lock(&portdev->c_ovq_lock);
if (virtqueue_add_buf(vq, sg, 1, 0, &cpkt, GFP_ATOMIC) >= 0) {
virtqueue_kick(vq);
while (!virtqueue_get_buf(vq, &len))
cpu_relax();
}
+ spin_unlock(&portdev->c_ovq_lock);
return 0;
}
@@ -1743,6 +1746,7 @@ static int __devinit virtcons_probe(struct virtio_device *vdev)
unsigned int nr_added_bufs;
spin_lock_init(&portdev->c_ivq_lock);
+ spin_lock_init(&portdev->c_ovq_lock);
INIT_WORK(&portdev->control_work, &control_work_handler);
nr_added_bufs = fill_queue(portdev->c_ivq,
This is a note to let you know that I have just added a patch titled virtio: console: add locking around c_ovq operations to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree which can be found at: http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.5.y.z tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Luis ------ From 60e6ac0f5c8f24b40a7f9f348804279df5641883 Mon Sep 17 00:00:00 2001 From: Amit Shah <amit.shah@redhat.com> Date: Fri, 29 Mar 2013 16:30:08 +0530 Subject: [PATCH] virtio: console: add locking around c_ovq operations commit 9ba5c80b1aea8648a3efe5f22dc1f7cacdfbeeb8 upstream. When multiple ovq operations are being performed (lots of open/close operations on virtio_console fds), the __send_control_msg() function can get confused without locking. A simple recipe to cause badness is: * create a QEMU VM with two virtio-serial ports * in the guest, do while true;do echo abc >/dev/vport0p1;done while true;do echo edf >/dev/vport0p2;done In one run, this caused a panic in __send_control_msg(). In another, I got virtio_console virtio0: control-o:id 0 is not a head! This also results repeated messages similar to these on the host: qemu-kvm: virtio-serial-bus: Unexpected port id 478762112 for device virtio-serial-bus.0 qemu-kvm: virtio-serial-bus: Unexpected port id 478762368 for device virtio-serial-bus.0 Reported-by: FuXiangChun <xfu@redhat.com> Signed-off-by: Amit Shah <amit.shah@redhat.com> Reviewed-by: Wanlong Gao <gaowanlong@cn.fujitsu.com> Reviewed-by: Asias He <asias@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> [ luis: adjust context ] Signed-off-by: Luis Henriques <luis.henriques@canonical.com> --- drivers/char/virtio_console.c | 4 ++++ 1 file changed, 4 insertions(+) -- 1.8.1.2