From d7a62cd0332115d4c7c4689abea0d889a30d8349 Mon Sep 17 00:00:00 2001 From: Amit Shah Date: Fri, 4 Mar 2011 14:04:33 +1030 Subject: [PATCH] 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 CC: stable@kernel.org Signed-off-by: Amit Shah Signed-off-by: Rusty Russell Signed-off-by: Linus Torvalds --- drivers/char/virtio_console.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c index 490393186338..84b164d1eb2b 100644 --- a/drivers/char/virtio_console.c +++ b/drivers/char/virtio_console.c @@ -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; -- 2.20.1