Re: sysfs warnings since kernel 3.13-rc1: "WARNING: ... at fs/sysfs/group.c:214 sysfs_remove_group"

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Wed, Jan 08, 2014 at 09:01:38PM +0100, Frank Schäfer wrote:
> Am 07.01.2014 18:59, schrieb Tejun Heo:
> > Hello,
> >
> > cc'ing Mauro and quoting whole body for him.
> >
> > So, ummm, the sysfs rule was that any group below a device should be
> > removed before the device itself is removed; however, nothing really
> > checked whether this actually was the case.  We didn't care whether
> > the order was reversed and if somebody forgot to remove the group
> > afterwards, we just leaked it.  After this commit, sysfs now whines if
> > the order is reversed, so the warning.
> >
> > While this should probably be fixed from the v4l side, I'm really
> > skeptical we're gaining anything by requiring users to explicitly
> > remove groups during device removal.  In most cases, this is a
> > completely unnecessary task.  Maybe we should just hunt down all
> > remove_group calls and remove all the unnecessary ones.
> >
> > Thanks.
> What about the USB mass storage devices ?
> Is it just a coincidence that this happens with two completely different
> types of USB devices ?

Yes it is, there's a big long thread on the linux-usb and scsi mailing
lists about this, and the fix should be final soon.

thanks,

greg k-h