From: Takatoshi Akiyama Date: Mon, 27 Feb 2017 06:56:31 +0000 (+0900) Subject: serial: sh-sci: Fix panic when serial console and DMA are enabled X-Git-Tag: microblaze-4.13-rc1~144^2~63 X-Git-Url: http://git.monstr.eu/?a=commitdiff_plain;h=3c9101766b502a0163d1d437fada5801cf616be2;p=linux-2.6-microblaze.git serial: sh-sci: Fix panic when serial console and DMA are enabled 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 --- diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c index 9a47cc4f16a2..1df57461ece4 100644 --- a/drivers/tty/serial/sh-sci.c +++ b/drivers/tty/serial/sh-sci.c @@ -1985,11 +1985,13 @@ static int sci_startup(struct uart_port *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); + } return 0; } @@ -2021,8 +2023,8 @@ 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,