Commit d7a62cd0 authored Mar 04, 2011 by Amit Shah Committed by Linus Torvalds Mar 06, 2011

virtio: console: Don't access vqs if device was unplugged



If a virtio-console device gets unplugged while a port is open, a
subsequent close() call on the port accesses vqs to free up buffers.
This can lead to a crash.

The buffers are already freed up as a result of the call to
unplug_ports() from virtcons_remove().  The fix is to simply not access
vq information if port->portdev is NULL.

Reported-by: juzhang <juzhang@redhat.com>
CC: stable@kernel.org
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent fb62c00a

drivers/char/virtio_console.c

+8 −0

Original line number	Diff line number	Diff line
		@@ -388,6 +388,10 @@ static void discard_port_data(struct port *port)
		unsigned int len;
		int ret;

		if (!port->portdev) {
		/* Device has been unplugged. vqs are already gone. */
		return;
		}
		vq = port->in_vq;
		if (port->inbuf)
		buf = port->inbuf;
		@@ -470,6 +474,10 @@ static void reclaim_consumed_buffers(struct port *port)
		void *buf;
		unsigned int len;

		if (!port->portdev) {
		/* Device has been unplugged. vqs are already gone. */
		return;
		}
		while ((buf = virtqueue_get_buf(port->out_vq, &len))) {
		kfree(buf);
		port->outvq_full = false;