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Date: Tue, 11 Apr 2006 12:43:56 -0700 (PDT)
From: Mikkel Erup <mikkelerup@yahoo.com>
Subject: Re: sdhci driver produces kernel oops on ejecting the card
To: Pierre Ossman <drzeus-list@drzeus.cx>
Cc: Greg KH <greg@kroah.com>, Andrew Morton <akpm@osdl.org>,
       Russell King <rmk+lkml@arm.linux.org.uk>, linux-kernel@vger.kernel.org
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> --- Russell King <rmk+lkml@arm.linux.org.uk> wrote:
> 
> > So the
> > only place for sane
> > refcounting seems to be genhd.c, as per the patch
> > below.
> > 
> > Comments?
> > 
> > diff -up -x BitKeeper -x ChangeSet -x SCCS -x _xlk
> -x
> > *.orig -x *.rej -x .git a/block/genhd.c
> > b/block/genhd.c
> > --- a/block/genhd.c	Sat Feb 18 10:31:37 2006
> > +++ b/block/genhd.c	Fri Apr  7 15:22:21 2006
> > @@ -262,6 +262,7 @@ static int exact_lock(dev_t
> dev,
> > void *d
> >   */
> >  void add_disk(struct gendisk *disk)
> >  {
> > +	get_device(disk->driverfs_dev);
> >  	disk->flags |= GENHD_FL_UP;
> >  	blk_register_region(MKDEV(disk->major,
> > disk->first_minor),
> >  			    disk->minors, NULL, exact_match,
> exact_lock,
> > disk);
> > @@ -507,6 +508,7 @@ static struct attribute *
> > default_attrs[
> >  static void disk_release(struct kobject * kobj)
> >  {
> >  	struct gendisk *disk = to_disk(kobj);
> > +	put_device(disk->driverfs_dev);
> >  	kfree(disk->random);
> >  	kfree(disk->part);
> >  	free_disk_stats(disk);
> 
> I can confirm that this patch is working.
> The 2.6.16-git20 kernel doesn't oops on
> ejecting the card after the patch is applied.
> 
> Mikkel

I didn't see anything regarding this on sdchi-devel or lkml for a
week or so, so I thought I'd just make sure it's not forgotten.
This patch works really well for me. The kernel no longer oopses
on ejecting the card because a NULL pointer is no longer
dereferenced and I think the patch should be considered.

Mikkel

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