[PATCH v3] pxa2xx_spi: fix memory corruption

[Marek Vasut]

> On Sunday 10 July 2011 18:18:19 Vasily Khoruzhick wrote:
> > pxa2xx_spi_probe allocates struct driver_data and null_dma_buf
> > at same time via spi_alloc_master(), but then calculates
> > null_dma_buf pointer incorrectly, and it causes memory corruption
> > later if DMA usage is enabled.
> 
> Ping?

Pong!

> 
> > Signed-off-by: Vasily Khoruzhick <anarsoul at gmail.com>
> > ---
> > v2: - add u8 __null_dma_buf[16] to the end of driver_data structure
> > and use it as null_dma_buf after alignment.
> > - use PTR_ALIGN instead of ALIGN
> > v3: - drop (u8 *) cast, use & operator instead, change array name
> > drivers/spi/pxa2xx_spi.c |       9 +++++----
> > 1 files changed, 5 insertions(+), 4 deletions(-)
> > 
> > diff --git a/drivers/spi/pxa2xx_spi.c b/drivers/spi/pxa2xx_spi.c
> > index dc25bee..b25fe27 100644
> > --- a/drivers/spi/pxa2xx_spi.c
> > +++ b/drivers/spi/pxa2xx_spi.c
> > @@ -106,6 +106,7 @@ struct driver_data {
> >     int rx_channel;
> >     int tx_channel;
> >     u32 *null_dma_buf;
> > +    u8 null_dma_buf_unaligned[16];
> > 
> >     /* SSP register addresses */
> >     void __iomem *ioaddr;
> > @@ -1543,8 +1544,8 @@ static int __devinit pxa2xx_spi_probe(struct
> > platform_device *pdev) return -ENODEV;
> >     }
> > 
> > -    /* Allocate master with space for drv_data and null dma buffer */
> > -    master = spi_alloc_master(dev, sizeof(struct driver_data) + 16);
> > +    /* Allocate master with space for drv_data */
> > +    master = spi_alloc_master(dev, sizeof(struct driver_data));
> >     if (!master) {
> >         dev_err(&pdev->dev, "cannot alloc spi_master\n");
> >         pxa_ssp_free(ssp);
> > @@ -1569,8 +1570,8 @@ static int __devinit pxa2xx_spi_probe(struct
> > platform_device *pdev) master->transfer = transfer;
> > 
> >     drv_data->ssp_type = ssp->type;
> > -    drv_data->null_dma_buf = (u32 *)ALIGN((u32)(drv_data +
> > -                        sizeof(struct driver_data)), 8);
> > +    drv_data->null_dma_buf =
> > +        (u32 *)PTR_ALIGN(&drv_data->null_dma_buf_unaligned, 8);
> > 
> >     drv_data->ioaddr = ssp->mmio_base;
> >     drv_data->ssdr_physical = ssp->phys_base + SSDR;