[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, 9 insertions, 9 deletions

diff --git a/drivers/char/watchdog/machzwd.c b/drivers/char/watchdog/machzwd.c
index 76c7fa37fa6c..a0d27160c80e 100644
--- a/drivers/char/watchdog/machzwd.c
+++ b/drivers/char/watchdog/machzwd.c
@@ -440,13 +440,6 @@ static int __init zf_init(void)
         spin_lock_init(&zf_lock);
         spin_lock_init(&zf_port_lock);
 
-        ret = misc_register(&zf_miscdev);
-        if (ret){
-                printk(KERN_ERR "can't misc_register on minor=%d\n",
-                                                        WATCHDOG_MINOR);
-                goto out;
-        }
-
         if(!request_region(ZF_IOBASE, 3, "MachZ ZFL WDT")){
                 printk(KERN_ERR "cannot reserve I/O ports at %d\n",
                                                         ZF_IOBASE);
@@ -461,16 +454,23 @@ static int __init zf_init(void)
                 goto no_reboot;
         }
 
+        ret = misc_register(&zf_miscdev);
+        if (ret){
+                printk(KERN_ERR "can't misc_register on minor=%d\n",
+                                                        WATCHDOG_MINOR);
+                goto no_misc;
+        }
+
         zf_set_status(0);
         zf_set_control(0);
 
         return 0;
 
+no_misc:
+        unregister_reboot_notifier(&zf_notifier);
 no_reboot:
         release_region(ZF_IOBASE, 3);
 no_region:
-        misc_deregister(&zf_miscdev);
-out:
         return ret;
 }