[PATCH] slab: add additional debugging to detect slabs from the wrong node

This patch adds some stack dumps if the slab logic is processing slab
blocks from the wrong node.  This is necessary in order to detect
situations as encountered by Petr.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 4 insertions, 1 deletions

diff --git a/mm/slab.c b/mm/slab.c
index d30423f167a2..22bfb0b2ac8b 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -2419,6 +2419,7 @@ retry:
                         next = slab_bufctl(slabp)[slabp->free];
 #if DEBUG
                         slab_bufctl(slabp)[slabp->free] = BUFCTL_FREE;
+                        WARN_ON(numa_node_id() != slabp->nodeid);
 #endif
                         slabp->free = next;
                 }
@@ -2633,8 +2634,10 @@ static void free_block(kmem_cache_t *cachep, void **objpp, int nr_objects, int n
                 check_spinlock_acquired_node(cachep, node);
                 check_slabp(cachep, slabp);
 
-
 #if DEBUG
+                /* Verify that the slab belongs to the intended node */
+                WARN_ON(slabp->nodeid != node);
+
                 if (slab_bufctl(slabp)[objnr] != BUFCTL_FREE) {
                         printk(KERN_ERR "slab: double free detected in cache "
                                         "'%s', objp %p\n", cachep->name, objp);