Add terminated list for keeping descriptor so that it could be freed in worker without any potential involving next descriptor raised up before this descriptor freed, because vchan_get_all_descriptors get all descriptors including the last terminated descriptor and the next descriptor, hence, the next descriptor maybe freed unexpectly when it's done in worker without this patch. https://www.spinics.net/lists/dmaengine/msg23367.html Signed-off-by: Robin Gong <yibin.gong@xxxxxxx> Reported-by: Richard Leitner <richard.leitner@xxxxxxxxxxx> Reviewed-by: Lucas Stach <l.stach@xxxxxxxxxxxxxx> --- drivers/dma/imx-sdma.c | 17 ++++++++++------- 1 file changed, 10 insertions(+), 7 deletions(-) diff --git a/drivers/dma/imx-sdma.c b/drivers/dma/imx-sdma.c index c449755..6e0490d 100644 --- a/drivers/dma/imx-sdma.c +++ b/drivers/dma/imx-sdma.c @@ -439,6 +439,7 @@ struct sdma_channel { enum dma_status status; struct imx_dma_data data; struct work_struct terminate_worker; + struct list_head terminated; bool is_ram_script; }; @@ -1107,9 +1108,6 @@ static void sdma_channel_terminate_work(struct work_struct *work) { struct sdma_channel *sdmac = container_of(work, struct sdma_channel, terminate_worker); - unsigned long flags; - LIST_HEAD(head); - /* * According to NXP R&D team a delay of one BD SDMA cost time * (maximum is 1ms) should be added after disable of the channel @@ -1118,10 +1116,7 @@ static void sdma_channel_terminate_work(struct work_struct *work) */ usleep_range(1000, 2000); - spin_lock_irqsave(&sdmac->vc.lock, flags); - vchan_get_all_descriptors(&sdmac->vc, &head); - spin_unlock_irqrestore(&sdmac->vc.lock, flags); - vchan_dma_desc_free_list(&sdmac->vc, &head); + vchan_dma_desc_free_list(&sdmac->vc, &sdmac->terminated); } static int sdma_terminate_all(struct dma_chan *chan) @@ -1135,6 +1130,13 @@ static int sdma_terminate_all(struct dma_chan *chan) if (sdmac->desc) { vchan_terminate_vdesc(&sdmac->desc->vd); + /* + * move out current descriptor into terminated list so that + * it could be free in sdma_channel_terminate_work alone + * later without potential involving next descriptor raised + * up before the last descriptor terminated. + */ + vchan_get_all_descriptors(&sdmac->vc, &sdmac->terminated); sdmac->desc = NULL; schedule_work(&sdmac->terminate_worker); } @@ -2132,6 +2134,7 @@ static int sdma_probe(struct platform_device *pdev) sdmac->channel = i; sdmac->vc.desc_free = sdma_desc_free; + INIT_LIST_HEAD(&sdmac->terminated); INIT_WORK(&sdmac->terminate_worker, sdma_channel_terminate_work); /* -- 2.7.4
