From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marek Vasut Subject: Re: [PATCH v3] pxa2xx_spi: fix memory corruption Date: Tue, 29 Nov 2011 15:31:55 +0100 Message-ID: <201111291531.56138.marek.vasut@gmail.com> References: <201107101609.31405.anarsoul@gmail.com> <201107181056.51782.anarsoul@gmail.com> <1322575504.7024.0.camel@anarsoul-laptop> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: David Brownell , Russell King - ARM Linux , Eric Miao , spi-devel-general-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org To: Vasily Khoruzhick Return-path: In-Reply-To: <1322575504.7024.0.camel@anarsoul-laptop> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: spi-devel-general-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Id: linux-spi.vger.kernel.org > On Mon, 2011-07-18 at 10:56 +0300, Vasily Khoruzhick wrote: > > On Friday 15 July 2011 05:53:31 Grant Likely wrote: > > > On Sun, Jul 10, 2011 at 06:18:19PM +0300, 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 > > > > --- > > > > 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]; > > > > > > Don't dma buffers need to be cache-line aligned? > > > > No, on PXA2xx they need to be 8-bytes aligned (according to PXA27x > > developer's manual) > > > > > How large is the actual transfer? > > > > Looks like 8 bytes, but I'm not sure, I'm not author of driver and did > > not dig deeply into its code. Just attempting to fix memory corruption. > > > > > Using the __aligned() or __cacheline_aligned > > > attribute is the correct way to make sure you've got a data buffer > > > that can be used for DMA mixed with other stuff. Then you don't need > > > to fool around with PTR_ALIGN or anything. > > > > Errr, it can't be applied to struct field, right? But driver needs > > per-device null_dma_buf (there's 3 SPI controllers on PXA2xx) > > > > > g. > > > > Regards > > Vasily > > So, any chance to see this patch merged? > > Regards > Vasily I have no idea, were all problems addressed ? M ------------------------------------------------------------------------------ All the data continuously generated in your IT infrastructure contains a definitive record of customers, application performance, security threats, fraudulent activity, and more. Splunk takes this data and makes sense of it. IT sense. And common sense. http://p.sf.net/sfu/splunk-novd2d