cpu hotplug: slab: fix memory leak in cpu hotplug error path

This patch fixes memory leak in error path.

In reality, we don't need to call cpuup_canceled(cpu) for now.  But upcoming
cpu hotplug error handling change needs this.

Cc: Christoph Lameter <clameter@sgi.com>
Cc: Gautham R Shenoy <ego@in.ibm.com>
Acked-by: NPekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
Cc: Gautham R Shenoy <ego@in.ibm.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

mm/slab.c

@@ -1282,13 +1282,18 @@ static int __cpuinit cpuup_prepare(long cpu)
 			shared = alloc_arraycache(node,
 				cachep->shared * cachep->batchcount,
 				0xbaadf00d);
-			if (!shared)
+			if (!shared) {
+				kfree(nc);
 				goto bad;
+			}
 		}
 		if (use_alien_caches) {
 			alien = alloc_alien_cache(node, cachep->limit);
-			if (!alien)
+			if (!alien) {
+				kfree(shared);
+				kfree(nc);
 				goto bad;
+			}
 		}
 		cachep->array[cpu] = nc;
 		l3 = cachep->nodelists[node];
@@ -1315,6 +1320,7 @@ static int __cpuinit cpuup_prepare(long cpu)
 	}
 	return 0;
 bad:
+	cpuup_canceled(cpu);
 	return -ENOMEM;
 }