[4.2.y-ckt stable] Patch "video: fbdev: fsl: Fix kernel crash when diu_ops is not implemented" has been added to the 4.2.y-ckt tree

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    video: fbdev: fsl: Fix kernel crash when diu_ops is not implemented

to the linux-4.2.y-queue branch of the 4.2.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-4.2.y-queue

This patch is scheduled to be released in version 4.2.8-ckt2.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 4.2.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

---8<------------------------------------------------------------

>From 9a26669003002c11623ae3b3bd73688b75cf1a82 Mon Sep 17 00:00:00 2001
From: Wang Dongsheng <dongsheng.wang at freescale.com>
Date: Thu, 3 Dec 2015 09:54:12 +0800
Subject: video: fbdev: fsl: Fix kernel crash when diu_ops is not implemented

commit acfc1cc13fe5bc6d7a10afa624f1e560850ddad3 upstream.

If diu_ops is not implemented on platform, kernel will access a NULL
pointer. We need to check this pointer in DIU initialization.

Signed-off-by: Wang Dongsheng <dongsheng.wang at freescale.com>
Acked-by: Timur Tabi <timur at tabi.org>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen at ti.com>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/video/fbdev/fsl-diu-fb.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/drivers/video/fbdev/fsl-diu-fb.c b/drivers/video/fbdev/fsl-diu-fb.c
index 7fa2e6f..2a1fde6 100644
--- a/drivers/video/fbdev/fsl-diu-fb.c
+++ b/drivers/video/fbdev/fsl-diu-fb.c
@@ -479,7 +479,10 @@ static enum fsl_diu_monitor_port fsl_diu_name_to_port(const char *s)
 			port = FSL_DIU_PORT_DLVDS;
 	}

-	return diu_ops.valid_monitor_port(port);
+	if (diu_ops.valid_monitor_port)
+		port = diu_ops.valid_monitor_port(port);
+
+	return port;
 }

 /*
@@ -1908,6 +1911,14 @@ static int __init fsl_diu_init(void)
 #else
 	monitor_port = fsl_diu_name_to_port(monitor_string);
 #endif
+
+	/*
+	 * Must to verify set_pixel_clock. If not implement on platform,
+	 * then that means that there is no platform support for the DIU.
+	 */
+	if (!diu_ops.set_pixel_clock)
+		return -ENODEV;
+
 	pr_info("Freescale Display Interface Unit (DIU) framebuffer driver\n");

 #ifdef CONFIG_NOT_COHERENT_CACHE
--
1.9.1