[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>

diff --git a/mm/slab.c b/mm/slab.c
index d30423f..22bfb0b 100644 (file)
--- 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);