On Wed, 23 Dec 2009, Rafael J. Wysocki wrote:
> Hi,
>
> Something like the patch below is necessary to fix a new NULL pointer deref
> in usb_serial_probe() that appeared after the recent kfifo changes (in short,
> the kfifo changes modified the semantics of kfifo_alloc() that
> usb_serial_probe() reiled on).
>
> Thanks,
> Rafael
>
> ---
> drivers/usb/serial/usb-serial.c | 10 +++++++++-
> 1 file changed, 9 insertions(+), 1 deletion(-)
>
> Index: linux-2.6/drivers/usb/serial/usb-serial.c
> ===================================================================
> --- linux-2.6.orig/drivers/usb/serial/usb-serial.c
> +++ linux-2.6/drivers/usb/serial/usb-serial.c
> @@ -595,8 +595,10 @@ static void port_release(struct device *
> usb_free_urb(port->write_urb);
> usb_free_urb(port->interrupt_in_urb);
> usb_free_urb(port->interrupt_out_urb);
> - if (!IS_ERR(port->write_fifo) && port->write_fifo)
> + if (port->write_fifo) {
> kfifo_free(port->write_fifo);
> + kfree(port->write_fifo);
> + }
> kfree(port->bulk_in_buffer);
> kfree(port->bulk_out_buffer);
> kfree(port->interrupt_in_buffer);
> @@ -939,6 +941,12 @@ int usb_serial_probe(struct usb_interfac
> dev_err(&interface->dev, "No free urbs available\n");
> goto probe_error;
> }
> + port->write_fifo = kzalloc(sizeof(struct kfifo), GFP_KERNEL);
> + if (!port->write_fifo) {
> + dev_err(&interface->dev,
> + "Couldn't allocate write_fifo\n");
> + goto probe_error;
> + }
> if (kfifo_alloc(port->write_fifo, PAGE_SIZE, GFP_KERNEL))
> goto probe_error;
> buffer_size = le16_to_cpu(endpoint->wMaxPacketSize);
Although this would mean further changes elsewhere, doesn't it make
more sense to embed the struct kfifo directly in the usb_serial_port
structure instead of allocating it dynamically?
Alan Stern
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