[PATCH 3.2 03/70] video: fbdev: fsl: Fix kernel crash when diu_ops is not implemented

Ben Hutchings
2016-01-18T03:32:13Z

From: Wang Dongsheng <dongsheng.wang@freescale.com>

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@freescale.com>
Acked-by: Timur Tabi <timur@tabi.org>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
[bwh: Backported to 3.2: adjust filename]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
drivers/video/fbdev/fsl-diu-fb.c | 13 ++++++++++++-
1 file changed, 12 insertions(+), 1 deletion(-)

--- a/drivers/video/fsl-diu-fb.c
+++ b/drivers/video/fsl-diu-fb.c
@@ -446,7 +446,10 @@ static enum fsl_diu_monitor_port fsl_diu
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;
}

/**
@@ -1759,6 +1762,14 @@ 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