Re: /sys/devices/system/timer registered twice

[Greg KH <greg@kroah.com>]

On Tue, Nov 09, 2004 at 08:30:43PM +0100, Kay Sievers wrote:
> Hi,
> I got this on a Centrino box with the latest bk:
> 
>   [kay@pim linux.kay]$ ls -l /sys/devices/system/
>   total 0
>   drwxr-xr-x  7 root root 0 Nov  8 15:12 .
>   drwxr-xr-x  5 root root 0 Nov  8 15:12 ..
>   drwxr-xr-x  3 root root 0 Nov  8 15:12 cpu
>   drwxr-xr-x  3 root root 0 Nov  8 15:12 i8259
>   drwxr-xr-x  2 root root 0 Nov  8 15:12 ioapic
>   drwxr-xr-x  3 root root 0 Nov  8 15:12 irqrouter
>   ?---------  ? ?    ?    ?            ? timer
> 
> 
> It is caused by registering two devices with the name "timer" from:
> 
>   arch/i386/kernel/time.c
>   arch/i386/kernel/timers/timer_pit.c
> 
> If I change one of the names, I get two correct looking sysfs entries.
> 
> Greg, shouldn't the driver core prevent the corruption of the first
> device if another one tries to register with the same name?

Yes, we should handle this.  Can you try the patch below?  I just sent
it to Linus, as it fixes a bug that was recently introduced.

The second registration should fail, and this patch will make it fail,
and recover properly.

thanks,

greg k-h

--- a/lib/kobject.c	2004-11-05 10:06:33 -08:00
+++ b/lib/kobject.c	2004-11-08 23:58:02 -08:00
@@ -181,10 +181,10 @@ int kobject_add(struct kobject * kobj)
 
 	error = create_dir(kobj);
 	if (error) {
+		/* Does the kobject_put() for us */
 		unlink(kobj);
 		if (parent)
 			kobject_put(parent);
-		kobject_put(kobj);
 	} else {
 		kobject_hotplug(kobj, KOBJ_ADD);
 	}