Messages in this thread | | | Date | Mon, 12 Sep 2005 16:44:48 +0200 | From | Bartlomiej Zolnierkiewicz <> | Subject | Re: [PATCH] fix kernel oops with CF-Cards |
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On 9/6/05, Thomas Kleffel <tk@maintech.de> wrote: > Hello,
Hi,
> when a mounted CF-Card is removed from the system, inserted back into > the slot, removed again, and then umount is called for that device the > kernel oopes. > > (This is a slightly different issue than noted in my last mail.) > > This happens because the reference counting gets confused. When a disk > gets released by ide_disk_release() it sets the driver_data member of > the corresponding drive to NULL. This is bad, as the pyhsical drive > could be assigned to another idkp structure in the meantime (happens, > when the drive is removed and inserted again).
As another idkp structure is a new object so still keeping the reference to the old one is a bug. It looks like the real problem here is that there are still references to the old idkp object while it is already gone.
Please see my previous mail.
Thanks, Bartlomiej
> My fix is to simply leave the drive alone when a disk is released. This > shouldn't cause any side-effects - drive->driver_data isn't tested for > containing NULL anywhere. > > The following patch (against vanilla 2.6.13) fixes that problem: > > diff -uprN -X b/Documentation/dontdiff a/drivers/ide/ide-disk.c > b/drivers/ide/ide-disk.c > --- a/drivers/ide/ide-disk.c 2005-08-24 17:58:02.000000000 +0200 > +++ b/drivers/ide/ide-disk.c 2005-09-05 02:10:30.000000000 +0200 > @@ -1048,11 +1048,8 @@ static int ide_disk_remove(struct device > static void ide_disk_release(struct kref *kref) > { > struct ide_disk_obj *idkp = to_ide_disk(kref); > - ide_drive_t *drive = idkp->drive; > struct gendisk *g = idkp->disk; > > - drive->driver_data = NULL; > - drive->devfs_name[0] = '\0'; > g->private_data = NULL; > put_disk(g); > kfree(idkp); > > Signed-off-by: Thomas Kleffel <tk@maintech.de> > > Best regards, > Thomas - 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/
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