On Sunday, July 10, 2011 02:09:22 PM 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.
>
> Signed-off-by: Vasily Khoruzhick <anars...@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
> 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..25358cd 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[16];
Ah, please don't name it starting with two underscores.
>
> /* 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((u8 *)drv_data->__null_dma_buf, 8);
Do you need that (u8 *) cast there ?
#define PTR_ALIGN(p, a) ((typeof(p))ALIGN((unsigned long)(p), (a)))
from linux/kernel.h line 42
>
> drv_data->ioaddr = ssp->mmio_base;
> drv_data->ssdr_physical = ssp->phys_base + SSDR;
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