tree:   git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-stable-rt.git stable-rt/v3.2-rt
head:   fb6e7f579bdf51611e4c6f848e5af607f2a17af2
commit: b9ebc2fa44a438920dc87da9b3da4a7ee8c16576 [513/519] mm/slub: move slab initialization into irq enabled region
config: x86_64-acpi-redef (attached as .config)
reproduce:
  git checkout b9ebc2fa44a438920dc87da9b3da4a7ee8c16576
  # save the attached .config to linux build tree
  make ARCH=x86_64 

All warnings (new ones prefixed by >>):

   mm/slub.c: In function 'allocate_slab':
>> mm/slub.c:1291:11: warning: unused variable 'order' [-Wunused-variable]
     int idx, order;
              ^
   mm/slub.c:1291:6: warning: unused variable 'idx' [-Wunused-variable]
     int idx, order;
         ^
   mm/slub.c: In function 'show_slab_objects':
   mm/slub.c:4490:11: warning: 'x' may be used uninitialized in this function [-Wmaybe-uninitialized]
        total += x;
              ^

vim +/order +1291 mm/slub.c

  1275		int order = oo_order(oo);
  1276	
  1277		flags |= __GFP_NOTRACK;
  1278	
  1279		if (node == NUMA_NO_NODE)
  1280			return alloc_pages(flags, order);
  1281		else
  1282			return alloc_pages_exact_node(node, flags, order);
  1283	}
  1284	
  1285	static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
  1286	{
  1287		struct page *page;
  1288		struct kmem_cache_order_objects oo = s->oo;
  1289		gfp_t alloc_gfp;
  1290		void *start, *last, *p;
> 1291		int idx, order;
  1292	
  1293		flags &= gfp_allowed_mask;
  1294	
  1295		if (flags & __GFP_WAIT)
  1296			local_irq_enable();
  1297	
  1298		flags |= s->allocflags;
  1299	

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