Re: ubifs: error unwinding trouble

From: Artem Bityutskiy
Date: Fri Jul 24 2009 - 08:18:48 EST


On Fri, 2009-07-24 at 13:49 +0300, Adrian Hunter wrote:
> Daniel Mack wrote:
> > On a recent git kernel, the error unwinding for UBIFS seems to have some
> > problem, most probably a double-free or something similar.
> >
> > When UBI is pointed to the right mtd partition (using command line
> > arguments) , everything is fine. But when it's (accidentionally) set to
> > some very small mtd, the attach process fails. Which wouldn't be a bad
> > thing by itself, but it somehow messes up the slub/slab allocators then
> > which causes very strange memory corruption effects - see the backtrace
> > below.
> >
> > The Ooops itself is unreleated to UBI, but it does not occur when UBI
> > succeeds in attaching the volume.
> >
> > Any idea? I searched for awhile but couldn't see anything obvious.
>
> Looks like a double free of the eba_tbl
>
> This might help:
>
> diff --git a/drivers/mtd/ubi/eba.c b/drivers/mtd/ubi/eba.c
> index 0f2034c..e4d9ef0 100644
> --- a/drivers/mtd/ubi/eba.c
> +++ b/drivers/mtd/ubi/eba.c
> @@ -1254,6 +1254,7 @@ out_free:
> if (!ubi->volumes[i])
> continue;
> kfree(ubi->volumes[i]->eba_tbl);
> + ubi->volumes[i]->eba_tbl = NULL;
> }
> return err;
> }

You are right. I've just pushed your patch to ubi-2.6.git/master.

--
Best Regards,
Artem Bityutskiy (ÐÑÑÑÐ ÐÐÑÑÑÐÐÐ)

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