Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262621AbUKLVbv (ORCPT ); Fri, 12 Nov 2004 16:31:51 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262622AbUKLVa4 (ORCPT ); Fri, 12 Nov 2004 16:30:56 -0500 Received: from e6.ny.us.ibm.com ([32.97.182.106]:22768 "EHLO e6.ny.us.ibm.com") by vger.kernel.org with ESMTP id S262623AbUKLVaY (ORCPT ); Fri, 12 Nov 2004 16:30:24 -0500 Date: Fri, 12 Nov 2004 12:50:27 -0800 From: Greg KH To: Maneesh Soni Cc: Kay Sievers , linux-kernel@vger.kernel.org Subject: Re: /sys/devices/system/timer registered twice Message-ID: <20041112205026.GG1711@kroah.com> References: <20041109193043.GA8767@vrfy.org> <20041109193947.GA5758@kroah.com> <20041110022535.GA10011@vrfy.org> <20041110223629.GA5925@in.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20041110223629.GA5925@in.ibm.com> User-Agent: Mutt/1.5.6i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2785 Lines: 70 On Wed, Nov 10, 2004 at 04:36:29PM -0600, Maneesh Soni wrote: > On Wed, Nov 10, 2004 at 03:25:35AM +0100, Kay Sievers wrote: > > On Tue, Nov 09, 2004 at 11:39:47AM -0800, Greg KH wrote: > > > 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. > > > > Yes, the registration fails. But it seems that the second call to > > create_dir(kobj) with a kobject with the same name and parent corrupts > > the dentry from the first call. > > > > To test it, I just called create_dir(kobj) a second time for my video > > driver and the sysfs entry of the successful registered kobject was > > corrupted: > > > > [kay@pim ~]$ ls -la /sys/class/video4linux/ > > total 0 > > drwxr-xr-x 3 root root 0 Nov 10 02:53 . > > drwxr-xr-x 18 root root 0 Nov 10 02:53 .. > > ?--------- ? ? ? ? ? video0 > > > > Thanks for reporting this bug. I think the problem here is doing d_drop() > for the existing directory dentry in create_dir() for error case. It should > not be done for EEXIST. Could you please try the same test with the following > patch applied. > > Thanks > Maneesh > > o Do not release existing directory if the new directory happens to be a > duplicate directory. Thanks to Kay Sievers for the testcase. > > Signed-off-by: Applied, thanks. greg k-h - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/