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 (file)
--- 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 (file)
--- 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);