From 135e5d48d5340a13dde43d38193fb58f661e8d47 Mon Sep 17 00:00:00 2001 From: Takatoshi Akiyama Date: Mon, 27 Feb 2017 15:56:31 +0900 Subject: [PATCH] serial: sh-sci: Fix panic when serial console and DMA are enabled 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 [Shimoda changes the commit log] Signed-off-by: Yoshihiro Shimoda Signed-off-by: Greg Kroah-Hartman [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings --- drivers/tty/serial/sh-sci.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c index 07c01348eb35..60f71ec60992 100644 --- a/drivers/tty/serial/sh-sci.c +++ b/drivers/tty/serial/sh-sci.c @@ -1579,11 +1579,13 @@ static int sci_startup(struct uart_port *port) sci_port_enable(s); + 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); + } sci_start_tx(port); sci_start_rx(port); @@ -1600,8 +1602,8 @@ static void sci_shutdown(struct uart_port *port) sci_stop_rx(port); sci_stop_tx(port); - sci_free_dma(port); sci_free_irq(s); + sci_free_dma(port); sci_port_disable(s); } -- 2.39.5