[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>
diff --git a/drivers/char/watchdog/ibmasr.c b/drivers/char/watchdog/ibmasr.c
index 8195f50..94155f6 100644
--- a/drivers/char/watchdog/ibmasr.c
+++ b/drivers/char/watchdog/ibmasr.c
@@ -367,18 +367,17 @@
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;
}