patch "serial: sh-sci: Do not free irqs that have already been freed" added to tty-linus

patch "serial: sh-sci: Do not free irqs that have already been freed" added to tty-linus

[gregkh]

This is a note to let you know that I've just added the patch titled

    serial: sh-sci: Do not free irqs that have already been freed

to my tty git tree which can be found at
    git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty.git
in the tty-linus branch.

The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)

The patch will hopefully also be merged in Linus's tree for the
next -rc kernel release.

If you have any questions about this process, please let me know.


From 4d95987a32db53f3beca76f8c4c8309ef6a5f192 Mon Sep 17 00:00:00 2001
From: Chris Brandt <chris.brandt@renesas.com>
Date: Mon, 28 Jan 2019 13:25:56 -0500
Subject: serial: sh-sci: Do not free irqs that have already been freed

Since IRQs might be muxed on some parts, we need to pay attention when we
are freeing them.
Otherwise we get the ugly WARNING "Trying to free already-free IRQ 20".

Fixes: 628c534ae735 ("serial: sh-sci: Improve support for separate TEI and DRI interrupts")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Chris Brandt <chris.brandt@renesas.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/tty/serial/sh-sci.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c
index 8df0fd824520..64bbeb7d7e0c 100644
--- a/drivers/tty/serial/sh-sci.c
+++ b/drivers/tty/serial/sh-sci.c
@@ -1921,7 +1921,7 @@ static int sci_request_irq(struct sci_port *port)
 
 static void sci_free_irq(struct sci_port *port)
 {
-	int i;
+	int i, j;
 
 	/*
 	 * Intentionally in reverse order so we iterate over the muxed
@@ -1937,6 +1937,13 @@ static void sci_free_irq(struct sci_port *port)
 		if (unlikely(irq < 0))
 			continue;
 
+		/* Check if already freed (irq was muxed) */
+		for (j = 0; j < i; j++)
+			if (port->irqs[j] == irq)
+				j = i + 1;
+		if (j > i)
+			continue;
+
 		free_irq(port->irqs[i], port);
 		kfree(port->irqstr[i]);
 
-- 
2.20.1