Re: [PATCH 1/3] spi/stmp: Fix device remove function

[Guenter Roeck <linux-0h96xk9xTtrk1uMJSBkQmQ@public.gmane.org>]

On Fri, Aug 24, 2012 at 10:47:08AM +0200, Wolfram Sang wrote:
> On Thu, Aug 23, 2012 at 08:08:47PM -0700, Guenter Roeck wrote:
> > The call sequence spi_alloc_master/spi_register_master/spi_unregister_master
> > is complete; it reduces the device reference count to zero, which results in
> > device memory being freed. The remove function accesses the freed memory after
> > the call to spi_unregister_master(), _and_ it calls spi_master_put on the freed
> > memory.
> > 
> > Acquire a reference to the SPI master device and release it after cleanup is
> > complete (with the existing spi_master_put) to solve the problem.
> > 
> > Also, the device subsystem ensures that the remove function is only called once,
> > and resets device driver data to NULL. Remove the respective check and drop the
> > unnecessaary call to platform_set_drvdata().
> > 
> > Signed-off-by: Guenter Roeck <linux-0h96xk9xTtrk1uMJSBkQmQ@public.gmane.org>
> > ---
> > Note that this driver is impossible to build, since it depends on ARCH_STMP3XXX
> > which is not defined anywhere.
> 
> It can be replaced with the spi driver for mxs once it is mainline.
> 
Maybe the driver should be removed then.

The mxs driver has exactly the same problem as the one fixed with this patch.
I'll submit a patch for it.

Guenter

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