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 4.4-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-4.4 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
@@ -1800,11 +1800,13 @@ 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);
@@ -1834,8 +1836,8 @@ static void sci_shutdown(struct uart_por
}
#endif
- 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-4.4/serial-sh-sci-fix-panic-when-serial-console-and-dma-are-enabled.patch