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serial: sh-sci: Fix panic when serial console and DMA are enabled

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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@ps.hitachi-solutions.com>
[Shimoda changes the commit log]
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Takatoshi Akiyama 2017-02-27 15:56:31 +09:00 committed by Greg Kroah-Hartman
parent 9ff4a1a36a
commit d952024873
1 changed files with 7 additions and 5 deletions
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12
drivers/tty/serial/sh-sci.c
View File

@ -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,