mm/slab: Fix crash during slab init
Chris Mason [Wed, 8 May 2013 19:56:28 +0000 (15:56 -0400)]
Commit 8a965b3baa89 ("mm, slab_common: Fix bootstrap creation of kmalloc
caches") introduced a regression that caused us to crash early during
boot.  The commit was introducing ordering of slab creation, making sure
two odd-sized slabs were created after specific powers of two sizes.

But, if any of the power of two slabs were created earlier during boot,
slabs at index 1 or 2 might not get created at all.  This patch makes
sure none of the slabs get skipped.

Tony Lindgren bisected this down to the offending commit, which really
helped because bisect kept bringing me to almost but not quite this one.

Signed-off-by: Chris Mason <chris.mason@fusionio.com>
Acked-by: Christoph Lameter <cl@linux.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Acked-by: Soren Brinkmann <soren.brinkmann@xilinx.com>
Tested-by: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Tested-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/slab_common.c

index d2517b0..ff3218a 100644 (file)
@@ -446,18 +446,18 @@ void __init create_kmalloc_caches(unsigned long flags)
                if (!kmalloc_caches[i]) {
                        kmalloc_caches[i] = create_kmalloc_cache(NULL,
                                                        1 << i, flags);
+               }
 
-                       /*
-                        * Caches that are not of the two-to-the-power-of size.
-                        * These have to be created immediately after the
-                        * earlier power of two caches
-                        */
-                       if (KMALLOC_MIN_SIZE <= 32 && !kmalloc_caches[1] && i == 6)
-                               kmalloc_caches[1] = create_kmalloc_cache(NULL, 96, flags);
+               /*
+                * Caches that are not of the two-to-the-power-of size.
+                * These have to be created immediately after the
+                * earlier power of two caches
+                */
+               if (KMALLOC_MIN_SIZE <= 32 && !kmalloc_caches[1] && i == 6)
+                       kmalloc_caches[1] = create_kmalloc_cache(NULL, 96, flags);
 
-                       if (KMALLOC_MIN_SIZE <= 64 && !kmalloc_caches[2] && i == 7)
-                               kmalloc_caches[2] = create_kmalloc_cache(NULL, 192, flags);
-               }
+               if (KMALLOC_MIN_SIZE <= 64 && !kmalloc_caches[2] && i == 7)
+                       kmalloc_caches[2] = create_kmalloc_cache(NULL, 192, flags);
        }
 
        /* Kmalloc array is now usable */