This is a note to let you know that I've just added the patch titled serial: sh-sci: Fix panic when serial console and DMA are enabled to the 3.18-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-sh-sci-fix-panic-when-serial-console-and-dma-are-enabled.patch and it can be found in the queue-3.18 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 3c9101766b502a0163d1d437fada5801cf616be2 Mon Sep 17 00:00:00 2001 From: Takatoshi Akiyama <takatoshi.akiyama.kj@xxxxxxxxxxxxxxxxxxxxxxxx> Date: Mon, 27 Feb 2017 15:56:31 +0900 Subject: serial: sh-sci: Fix panic when serial console and DMA are enabled From: Takatoshi Akiyama <takatoshi.akiyama.kj@xxxxxxxxxxxxxxxxxxxxxxxx> commit 3c9101766b502a0163d1d437fada5801cf616be2 upstream. This patch fixes an issue that kernel panic happens when DMA is enabled and we press enter key while the kernel booting on the serial console. * An interrupt may occur after sci_request_irq(). * DMA transfer area is initialized by setup_timer() in sci_request_dma() and used in interrupt. If an interrupt occurred between sci_request_irq() and setup_timer() in sci_request_dma(), DMA transfer area has not been initialized yet. So, this patch changes the order of sci_request_irq() and sci_request_dma(). Fixes: 73a19e4c0301 ("serial: sh-sci: Add DMA support.") Signed-off-by: Takatoshi Akiyama <takatoshi.akiyama.kj@xxxxxxxxxxxxxxxxxxxxxxxx> [Shimoda changes the commit log] Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx> Cc: Jiri Slaby <jslaby@xxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/tty/serial/sh-sci.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) --- a/drivers/tty/serial/sh-sci.c +++ b/drivers/tty/serial/sh-sci.c @@ -1734,11 +1734,13 @@ static int sci_startup(struct uart_port dev_dbg(port->dev, "%s(%d)\n", __func__, port->line); + sci_request_dma(port); + ret = sci_request_irq(s); - if (unlikely(ret < 0)) + if (unlikely(ret < 0)) { + sci_free_dma(port); return ret; - - sci_request_dma(port); + } spin_lock_irqsave(&port->lock, flags); sci_start_tx(port); @@ -1760,8 +1762,8 @@ static void sci_shutdown(struct uart_por sci_stop_tx(port); spin_unlock_irqrestore(&port->lock, flags); - sci_free_dma(port); sci_free_irq(s); + sci_free_dma(port); } static unsigned int sci_scbrr_calc(struct sci_port *s, unsigned int bps, Patches currently in stable-queue which might be from takatoshi.akiyama.kj@xxxxxxxxxxxxxxxxxxxxxxxx are queue-3.18/serial-sh-sci-fix-panic-when-serial-console-and-dma-are-enabled.patch