From c871ac4e9666ad68ae861172ef8a7f73d6e61b26 Mon Sep 17 00:00:00 2001
From: Andrew Morton <akpm@linux-foundation.org>
Date: Wed, 10 Dec 2014 15:42:25 -0800
Subject: 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 <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/slab.c b/mm/slab.c
index a2152a2..79e15f0 100644
--- 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
index cf4f3c4..386bbed 100644
--- 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);
-- 
cgit v0.10.2