Re: 2.6.21-rc7-mm2 crash: Eeek! page_mapcount(page) went negative! (-1)

["Kay Sievers" <kay.sievers@vrfy.org>]

On 5/2/07, Greg KH <gregkh@suse.de> wrote:
> On Wed, May 02, 2007 at 12:10:00AM -0700, Andrew Morton wrote:
> > On Wed, 02 May 2007 09:01:22 +0200 Tilman Schmidt <tilman@imap.cc> wrote:
> >
> > > Am 30.04.2007 21:46 schrieb Andrew Morton:
> > > > Not really - everything's tangled up.  A bisection search on the
> > > > 2.6.21-rc7-mm2 driver tree would be the best bet.
> > >
> > > And the winner is:
> > >
> > > gregkh-driver-driver-core-make-uevent-environment-available-in-uevent-file.patch
> > >
> > > Reverting only that from 2.6.21-rc7-mm2 gives me a working kernel
> > > again.
> >
> > cripes.
> >
> > +static ssize_t show_uevent(struct device *dev, struct device_attribute *attr,
> > +                          char *buf)
> > +{
> > +       struct kobject *top_kobj;
> > +       struct kset *kset;
> > +       char *envp[32];
> > +       char data[PAGE_SIZE];
> >
> > That won't work too well with 4k stacks.

Yeah, sorry.

> Wait, even though this isn't good, it shouldn't have been hit by anyone,
> that file used to not be readable, so I doubt userspace would have been
> trying to read it...
>
> Tilman, what version of HAL and udev do you have on your machine?
>
> Kay, did you get the 'read the uevent file' code already into udev
> and/or HAL?

Only udevtest uses this at the moment, but that is only used for debugging.
It's probably the brain-dead libsysfs, which opens and reads every
file in /sys, even when nobody is interested in the data.

Thanks,
Kay