Re: [PATCH] [DRIVER MODEL] Fix gbefb

[Russell King <rmk+lkml@arm.linux.org.uk>]

Statically allocated devices in module data is a potential cause
of oopsen.  The device may be in use by a userspace process, which
will keep a reference to the device.  If the module is unloaded,
the module data will be freed.  Subsequent use of the platform
device will cause a kernel oops.

Use generic platform device allocation/release code in modules.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

diff --git a/drivers/video/gbefb.c b/drivers/video/gbefb.c
--- a/drivers/video/gbefb.c
+++ b/drivers/video/gbefb.c
@@ -1254,17 +1254,22 @@ static struct device_driver gbefb_driver
 	.remove = __devexit_p(gbefb_remove),
 };
 
-static struct platform_device gbefb_device = {
-	.name = "gbefb",
-};
+static struct platform_device *gbefb_device;
 
 int __init gbefb_init(void)
 {
 	int ret = driver_register(&gbefb_driver);
 	if (!ret) {
-		ret = platform_device_register(&gbefb_device);
-		if (ret)
+		gbefb_device = platform_device_alloc("gbefb", 0);
+		if (gbefb_device) {
+			ret = platform_device_add(gbefb_device);
+		} else {
+			ret = -ENOMEM;
+		}
+		if (ret) {
+			platform_device_put(gbefb_device);
 			driver_unregister(&gbefb_driver);
+		}
 	}
 	return ret;
 }
@@ -1271,7 +1276,8 @@ int __init gbefb_init(void)
 
 void __exit gbefb_exit(void)
 {
-	 driver_unregister(&gbefb_driver);
+	platform_device_unregister(gbefb_device);
+	driver_unregister(&gbefb_driver);
 }
 
 module_init(gbefb_init);


-- 
Russell King
 Linux kernel    2.6 ARM Linux   - http://www.arm.linux.org.uk/
 maintainer of:  2.6 Serial core