[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/machzwd.c b/drivers/char/watchdog/machzwd.c
index 76c7fa3..a0d2716 100644
--- a/drivers/char/watchdog/machzwd.c
+++ b/drivers/char/watchdog/machzwd.c
@@ -440,13 +440,6 @@
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 @@
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;
}