[PATCH] Slab: Do not fallback to nodes that have not been bootstrapped yet

The zonelist may contain zones of nodes that have not been bootstrapped and
we will oops if we try to allocate from those zones.  So check if the node
information for the slab and the node have been setup before attempting an
allocation.  If it has not been setup then skip that zone.

Usually we will not encounter this situation since the slab bootstrap code
avoids falling back before we have setup the respective nodes but we seem
to have a special needs for pppc.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Acked-by: Andy Whitcroft <apw@shadowen.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Mike Kravetz <kravetz@us.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Acked-by: Will Schmidt <will_schmidt@vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/mm/slab.c b/mm/slab.c
index 266449d604bd170c4c1656318c1ded64fcc5404a..84c631f30741016e0e73602129ed6c33d6ca88f9 100644 (file)
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -3152,12 +3152,15 @@ void *fallback_alloc(struct kmem_cache *cache, gfp_t flags)
        struct zone **z;
        void *obj = NULL;
 
-       for (z = zonelist->zones; *z && !obj; z++)
+       for (z = zonelist->zones; *z && !obj; z++) {
+               int nid = zone_to_nid(*z);
+
                if (zone_idx(*z) <= ZONE_NORMAL &&
-                               cpuset_zone_allowed(*z, flags))
+                               cpuset_zone_allowed(*z, flags) &&
+                               cache->nodelists[nid])
                        obj = __cache_alloc_node(cache,
-                                       flags | __GFP_THISNODE,
-                                       zone_to_nid(*z));
+                                       flags | __GFP_THISNODE, nid);
+       }
        return obj;
 }