[WATCHDOG] Semi-typical watchdog bug re early misc_register()

It seems that some watchdog drivers are doing following mistake:

	rv = misc_register();
	if (rv < 0)
		return rv;
	rv = request_region();
	if (rv < 0) {
		misc_deregister();
		return rv;
	}

But, right after misc_register() returns, misc device can be opened and
ioctls interacting with hardware issued, and driver can do outb() to
port it doesn't own yet, because request_region() is still pending.

Here is my patch, compile-tested only.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

1 files changed, 5 insertions, 6 deletions

diff --git a/drivers/char/watchdog/ibmasr.c b/drivers/char/watchdog/ibmasr.c
index 8195f5023d85..94155f6136c2 100644
--- a/drivers/char/watchdog/ibmasr.c
+++ b/drivers/char/watchdog/ibmasr.c
@@ -367,18 +367,17 @@ static int __init ibmasr_init(void)
 	if (!asr_type)
 		return -ENODEV;
 
+	rc = asr_get_base_address();
+	if (rc)
+		return rc;
+
 	rc = misc_register(&asr_miscdev);
 	if (rc < 0) {
+		release_region(asr_base, asr_length);
 		printk(KERN_ERR PFX "failed to register misc device\n");
 		return rc;
 	}
 
-	rc = asr_get_base_address();
-	if (rc) {
-		misc_deregister(&asr_miscdev);
-		return rc;
-	}
-
 	return 0;
 }