Re: [Regression, 2.6.33-rc1->current git] NULL pointer in usb_serial_probe() introduced by the recent kfifo changes

From: Rafael J. Wysocki
Date: Wed Dec 23 2009 - 11:15:20 EST


On Wednesday 23 December 2009, Greg KH wrote:
> On Wed, Dec 23, 2009 at 02:51:31AM +0100, 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).
>
> What semantic changed? I thought that the kfifo patches came with
> patches that also fixed up any changed that were needed. What went
> wrong here?

Previously write_fifo was allocated by kfifo_alloc() along with the structure
members. Now kfifo_alloc() expects to get a pointer to existing structure.

> Does your patch solve the oops?

Sure, that's why I posted it. :-)

Rafael
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