[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/eurotechwdt.c b/drivers/char/watchdog/eurotechwdt.c
index f70387f..b070324 100644
--- a/drivers/char/watchdog/eurotechwdt.c
+++ b/drivers/char/watchdog/eurotechwdt.c
@@ -413,17 +413,10 @@
{
int ret;
- ret = misc_register(&eurwdt_miscdev);
- if (ret) {
- printk(KERN_ERR "eurwdt: can't misc_register on minor=%d\n",
- WATCHDOG_MINOR);
- goto out;
- }
-
ret = request_irq(irq, eurwdt_interrupt, IRQF_DISABLED, "eurwdt", NULL);
if(ret) {
printk(KERN_ERR "eurwdt: IRQ %d is not free.\n", irq);
- goto outmisc;
+ goto out;
}
if (!request_region(io, 2, "eurwdt")) {
@@ -438,6 +431,13 @@
goto outreg;
}
+ ret = misc_register(&eurwdt_miscdev);
+ if (ret) {
+ printk(KERN_ERR "eurwdt: can't misc_register on minor=%d\n",
+ WATCHDOG_MINOR);
+ goto outreboot;
+ }
+
eurwdt_unlock_chip();
ret = 0;
@@ -448,14 +448,14 @@
out:
return ret;
+outreboot:
+ unregister_reboot_notifier(&eurwdt_notifier);
+
outreg:
release_region(io, 2);
outirq:
free_irq(irq, NULL);
-
-outmisc:
- misc_deregister(&eurwdt_miscdev);
goto out;
}