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 <laurent.pinchart@xxxxxxxxxxxxxxxx> --- drivers/media/video/omap3isp/ispvideo.c | 8 ++++++++ 1 files changed, 8 insertions(+), 0 deletions(-) diff --git a/drivers/media/video/omap3isp/ispvideo.c b/drivers/media/video/omap3isp/ispvideo.c index fd94cdf..ba86f11 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; } -- 1.7.3.4 -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
