From d9520248733414e96fb534b99534ef1e761eda6e 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 Cc: Jiri Slaby Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/sh-sci.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c index 4b26252c2885..ee84f89391ca 100644 --- a/drivers/tty/serial/sh-sci.c +++ b/drivers/tty/serial/sh-sci.c @@ -1976,12 +1976,14 @@ static int sci_startup(struct uart_port *port) dev_dbg(port->dev, "%s(%d)\n", __func__, port->line); - ret = sci_request_irq(s); - if (unlikely(ret < 0)) - return ret; - sci_request_dma(port); + ret = sci_request_irq(s); + if (unlikely(ret < 0)) { + sci_free_dma(port); + return ret; + } + return 0; } @@ -2012,8 +2014,8 @@ static void sci_shutdown(struct uart_port *port) } #endif - sci_free_dma(port); sci_free_irq(s); + sci_free_dma(port); } static int sci_sck_calc(struct sci_port *s, unsigned int bps,