mtdchar kernel oops

[Joel Reardon]

I think that this patch:
"mtdchar: kill persistently held vfsmount"
http://permalink.gmane.org/gmane.linux.kernel.commits.head/314175

has started causing kernel oops's when running ubiformat. The oops is
occuring in fs/namespace.c's mnt_add_count() line:
        this_cpu_add(mnt->mnt_pcp->mnt_count, n);

with the stack trace:
mntget()
simple_pin_fs()
mtdchar_open()

Cheers,
Joel