slab: improve checking for invalid gfp_flags

The code goes BUG, but doesn't tell us which bits were unexpectedly set. Print that out. Cc: Christoph Lameter <[email protected]> Cc: Pekka Enberg <[email protected]> Cc: David Rientjes <[email protected]> Cc: Joonsoo Kim <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
chewitt · Dec 11, 2014 · c871ac4 · c871ac4
1 parent f6edde9
commit c871ac4
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Showing 2 changed files with 8 additions and 2 deletions.
diff --git a/mm/slab.c b/mm/slab.c
@@ -2590,7 +2590,10 @@ static int cache_grow(struct kmem_cache *cachep,
 	 * Be lazy and only check for valid flags here,  keeping it out of the
 	 * critical path in kmem_cache_alloc().
 	 */
-	BUG_ON(flags & GFP_SLAB_BUG_MASK);
+	if (unlikely(flags & GFP_SLAB_BUG_MASK)) {
+		pr_emerg("gfp: %u\n", flags & GFP_SLAB_BUG_MASK);
+		BUG();
+	}
 	local_flags = flags & (GFP_CONSTRAINT_MASK|GFP_RECLAIM_MASK);
 
 	/* Take the node list lock to change the colour_next on this node */

diff --git a/mm/slub.c b/mm/slub.c
@@ -1377,7 +1377,10 @@ static struct page *new_slab(struct kmem_cache *s, gfp_t flags, int node)
 	int order;
 	int idx;
 
-	BUG_ON(flags & GFP_SLAB_BUG_MASK);
+	if (unlikely(flags & GFP_SLAB_BUG_MASK)) {
+		pr_emerg("gfp: %u\n", flags & GFP_SLAB_BUG_MASK);
+		BUG();
+	}
 
 	page = allocate_slab(s,
 		flags & (GFP_RECLAIM_MASK | GFP_CONSTRAINT_MASK), node);