Re: 2.6.10-rc2-mm2 usb storage still oopses

Andrew Morton
2004-11-30T00:35:16Z

Pete Zaitcev <zaitcev@redhat.com> wrote:
>
> On Fri, 19 Nov 2004 00:42:40 +0100, Fabio Coatti <cova@ferrara.linux.it> wrote:
>
> > Nov 18 20:33:05 kefk kernel: sdb: assuming drive cache: write through
> > Nov 18 20:33:05 kefk kernel: sdb: sdb1
> > Nov 18 20:33:05 kefk kernel: sdb: sdb1
> > Nov 18 20:33:05 kefk kernel: kobject_register failed for sdb1 (-17)
>
> This looks as if SCSI falls victim of the general problem which ub addresses
> with the following fragment:

Guys, is this problem still present in Linus's tree? If so, is a fix for
2.6.10 looking feasible?

Thanks.

> --- linux-2.6.10-rc1/drivers/block/ub.c 2004-10-28 09:46:38.000000000 -0700
> +++ linux-2.6.10-rc1-ub/drivers/block/ub.c 2004-11-06 23:59:20.000000000 -0800
> @@ -267,6 +263,7 @@ struct ub_dev {
> int changed; /* Media was changed */
> int removable;
> int readonly;
> + int first_open; /* Kludge. See ub_bd_open. */
> char name[8];
> struct usb_device *dev;
> struct usb_interface *intf;
> @@ -1428,6 +1420,26 @@ static int ub_bd_open(struct inode *inod
> sc->openc++;
> spin_unlock_irqrestore(&ub_lock, flags);
>
> + /*
> + * This is a workaround for a specific problem in our block layer.
> + * In 2.6.9, register_disk duplicates the code from rescan_partitions.
> + * However, if we do add_disk with a device which persistently reports
> + * a changed media, add_disk calls register_disk, which does do_open,
> + * which will call rescan_paritions for changed media. After that,
> + * register_disk attempts to do it all again and causes double kobject
> + * registration and a eventually an oops on module removal.
> + *
> + * The bottom line is, Al Viro says that we should not allow
> + * bdev->bd_invalidated to be set when doing add_disk no matter what.
> + */
> + if (sc->first_open) {
> + if (sc->changed) {
> + sc->first_open = 0;
> + rc = -ENOMEDIUM;
> + goto err_open;
> + }
> + }
> +
> if (sc->removable || sc->readonly)
> check_disk_change(inode->i_bdev);
>
> @@ -1467,6 +1479,8 @@ static int ub_bd_release(struct inode *i
>
> spin_lock_irqsave(&ub_lock, flags);
> --sc->openc;
> + if (sc->openc == 0)
> + sc->first_open = 0;
> if (sc->openc == 0 && atomic_read(&sc->poison))
> ub_cleanup(sc);
> spin_unlock_irqrestore(&ub_lock, flags);
> @@ -1919,6 +1932,8 @@ static int ub_probe(struct usb_interface
> }
>
> sc->removable = 1; /* XXX Query this from the device */
> + sc->changed = 1; /* ub_revalidate clears only */
> + sc->first_open = 1;
>
> ub_revalidate(sc);
> /* This is pretty much a long term P3 */
>
> This feels kludgy, but my excuse is "James and Viro made me do it".
> I have an IRC log to prove it laying somewhere...
>
> I'm adding the linux-scsi to cc: in case any comments are forthcoming.
>
> -- Pete