There are two places, that do not release the slub_lock.
Respective bugs were introduced by sysfs changes 
ab4d5ed5 (slub: Enable
sysfs support for !CONFIG_SLUB_DEBUG) and 
2bce6485 ( slub: Allow removal
of slab caches during boot).
Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
                kfree(n);
                kfree(s);
        }
+err:
        up_write(&slub_lock);
 
-err:
        if (flags & SLAB_PANIC)
                panic("Cannot create slabcache %s\n", name);
        else
                        x += sprintf(buf + x, " N%d=%lu",
                                        node, nodes[node]);
 #endif
+       up_read(&slub_lock);
        kfree(nodes);
        return x + sprintf(buf + x, "\n");
 }