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

seebe · gregkh · commit 4d95987a32db · 2019-01-30T09:35:46.000+01:00
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: 628c534 ("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>
diff --git 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]);
 
