From 5b6c3ef0e43fe80b517735697e4d0fb5729b2ab4 Mon Sep 17 00:00:00 2001 From: Laurent Pinchart Date: Sat, 13 Aug 2011 13:13:32 -0300 Subject: [media] omap3isp: video: Avoid crashes when pipeline set stream operation fails If streaming can't be enabled on the pipeline, the DMA buffers queue is not emptied. If the buffers then get freed the queue will end up referencing free memory. This is usually not an issue, as the DMA queue will be reinitialized the next time streaming is enabled, before enabling the hardware. However, if the sensor connected at the pipeline input is free-running, the CCDC will start generating interrupts as soon as it gets powered up, before the streaming gets enabled on the hardware. This will make the CCDC interrupt handler access freed memory, causing a crash. Reinitialize the DMA buffers queue in isp_video_streamon() if the error path to make sure this situation won't happen. Signed-off-by: Laurent Pinchart Signed-off-by: Mauro Carvalho Chehab --- drivers/media/video/omap3isp/ispvideo.c | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'drivers/media') diff --git a/drivers/media/video/omap3isp/ispvideo.c b/drivers/media/video/omap3isp/ispvideo.c index fd94cdf471bc..ba86f119ebbc 100644 --- a/drivers/media/video/omap3isp/ispvideo.c +++ b/drivers/media/video/omap3isp/ispvideo.c @@ -1056,6 +1056,14 @@ error: if (video->isp->pdata->set_constraints) video->isp->pdata->set_constraints(video->isp, false); media_entity_pipeline_stop(&video->video.entity); + /* The DMA queue must be emptied here, otherwise CCDC interrupts + * that will get triggered the next time the CCDC is powered up + * will try to access buffers that might have been freed but + * still present in the DMA queue. This can easily get triggered + * if the above omap3isp_pipeline_set_stream() call fails on a + * system with a free-running sensor. + */ + INIT_LIST_HEAD(&video->dmaqueue); video->queue = NULL; } -- cgit v1.2.3