On Wednesday 23 December 2009, Alan Stern wrote:
> 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?
I guess it would, but I wanted to avoid making any further changes.
Rafael
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