commit fb8f7ba077b5c665432082ab205bcd2cb01f6a3c
author Alexey Dobriyan <adobriyan@gmail.com> Sat Mar 24 15:58:12 2007 +0300
committer Wim Van Sebroeck <wim@iguana.be> Mon Mar 26 20:26:11 2007 +0000
tree 13a956eb9a1723bd3d5463230acbfc6513f3b034
parent 0e94f2ee0d1947ba6c2c00c3e971ff93ce8edec1

[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>

drivers/char/watchdog/sbc8360.c

diff --git a/drivers/char/watchdog/sbc8360.c b/drivers/char/watchdog/sbc8360.c
index 67ae426..285d852 100644
--- a/drivers/char/watchdog/sbc8360.c
+++ b/drivers/char/watchdog/sbc8360.c
@@ -333,18 +333,17 @@
 	int res;
 	unsigned long int mseconds = 60000;
 
-	spin_lock_init(&sbc8360_lock);
-	res = misc_register(&sbc8360_miscdev);
-	if (res) {
-		printk(KERN_ERR PFX "failed to register misc device\n");
-		goto out_nomisc;
+	if (timeout < 0 || timeout > 63) {
+		printk(KERN_ERR PFX "Invalid timeout index (must be 0-63).\n");
+		res = -EINVAL;
+		goto out;
 	}
 
 	if (!request_region(SBC8360_ENABLE, 1, "SBC8360")) {
 		printk(KERN_ERR PFX "ENABLE method I/O %X is not available.\n",
 		       SBC8360_ENABLE);
 		res = -EIO;
-		goto out_noenablereg;
+		goto out;
 	}
 	if (!request_region(SBC8360_BASETIME, 1, "SBC8360")) {
 		printk(KERN_ERR PFX
@@ -360,10 +359,11 @@
 		goto out_noreboot;
 	}
 
-	if (timeout < 0 || timeout > 63) {
-		printk(KERN_ERR PFX "Invalid timeout index (must be 0-63).\n");
-		res = -EINVAL;
-		goto out_noreboot;
+	spin_lock_init(&sbc8360_lock);
+	res = misc_register(&sbc8360_miscdev);
+	if (res) {
+		printk(KERN_ERR PFX "failed to register misc device\n");
+		goto out_nomisc;
 	}
 
 	wd_margin = wd_times[timeout][0];
@@ -383,13 +383,13 @@
 
 	return 0;
 
-      out_noreboot:
-	release_region(SBC8360_ENABLE, 1);
-	release_region(SBC8360_BASETIME, 1);
-      out_noenablereg:
-      out_nobasetimereg:
-	misc_deregister(&sbc8360_miscdev);
       out_nomisc:
+	unregister_reboot_notifier(&sbc8360_notifier);
+      out_noreboot:
+	release_region(SBC8360_BASETIME, 1);
+      out_nobasetimereg:
+	release_region(SBC8360_ENABLE, 1);
+      out:
 	return res;
 }