This is a note to let you know that I've just added the patch titled serial: stm32: fix DMA initialization error handling to the 5.10-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: serial-stm32-fix-dma-initialization-error-handling.patch and it can be found in the queue-5.10 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 3837a77a7da9b0788bdfe341b017cce43c82e8b8 Author: Erwan Le Ray <erwan.leray@xxxxxxxxxxx> Date: Wed Jan 6 17:21:56 2021 +0100 serial: stm32: fix DMA initialization error handling [ Upstream commit e7997f7ff7f8154d477f6f976698d868a2ac3934 ] DMA initialization error handling is not properly implemented in the driver. Fix DMA initialization error handling by: - moving TX DMA descriptor request error handling in a new dedicated fallback_err label - adding error handling to TX DMA descriptor submission - adding error handling to RX DMA descriptor submission This patch depends on '24832ca3ee85 ("tty: serial: stm32-usart: Remove set but unused 'cookie' variables")' which unfortunately doesn't include a "Fixes" tag. Fixes: 3489187204eb ("serial: stm32: adding dma support") Signed-off-by: Erwan Le Ray <erwan.leray@xxxxxxxxxxx> Link: https://lore.kernel.org/r/20210106162203.28854-2-erwan.leray@xxxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c index f4de32d3f2af..6248304a001f 100644 --- a/drivers/tty/serial/stm32-usart.c +++ b/drivers/tty/serial/stm32-usart.c @@ -383,17 +383,18 @@ static void stm32_transmit_chars_dma(struct uart_port *port) DMA_MEM_TO_DEV, DMA_PREP_INTERRUPT); - if (!desc) { - for (i = count; i > 0; i--) - stm32_transmit_chars_pio(port); - return; - } + if (!desc) + goto fallback_err; desc->callback = stm32_tx_dma_complete; desc->callback_param = port; /* Push current DMA TX transaction in the pending queue */ - dmaengine_submit(desc); + if (dma_submit_error(dmaengine_submit(desc))) { + /* dma no yet started, safe to free resources */ + dmaengine_terminate_async(stm32port->tx_ch); + goto fallback_err; + } /* Issue pending DMA TX requests */ dma_async_issue_pending(stm32port->tx_ch); @@ -402,6 +403,11 @@ static void stm32_transmit_chars_dma(struct uart_port *port) xmit->tail = (xmit->tail + count) & (UART_XMIT_SIZE - 1); port->icount.tx += count; + return; + +fallback_err: + for (i = count; i > 0; i--) + stm32_transmit_chars_pio(port); } static void stm32_transmit_chars(struct uart_port *port) @@ -1130,7 +1136,11 @@ static int stm32_of_dma_rx_probe(struct stm32_port *stm32port, desc->callback_param = NULL; /* Push current DMA transaction in the pending queue */ - dmaengine_submit(desc); + ret = dma_submit_error(dmaengine_submit(desc)); + if (ret) { + dmaengine_terminate_sync(stm32port->rx_ch); + goto config_err; + } /* Issue pending DMA requests */ dma_async_issue_pending(stm32port->rx_ch);