kmemleak: Only use GFP_KERNEL|GFP_ATOMIC for the internal allocations

Kmemleak allocates memory for pointer tracking and it tries to avoid
using GFP_ATOMIC if the caller doesn't require it. However other gfp
flags may be passed by the caller which aren't required by kmemleak.
This patch filters the gfp flags so that only GFP_KERNEL | GFP_ATOMIC
are used.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>

mm/kmemleak.c

@@ -109,6 +109,9 @@
 
 #define BYTES_PER_POINTER	sizeof(void *)
 
+/* GFP bitmask for kmemleak internal allocations */
+#define GFP_KMEMLEAK_MASK	(GFP_KERNEL | GFP_ATOMIC)
+
 /* scanning area inside a memory block */
 struct kmemleak_scan_area {
 	struct hlist_node node;
@@ -462,7 +465,7 @@ static void create_object(unsigned long ptr, size_t size, int min_count,
 	struct prio_tree_node *node;
 	struct stack_trace trace;
 
-	object = kmem_cache_alloc(object_cache, gfp & ~GFP_SLAB_BUG_MASK);
+	object = kmem_cache_alloc(object_cache, gfp & GFP_KMEMLEAK_MASK);
 	if (!object) {
 		kmemleak_panic("kmemleak: Cannot allocate a kmemleak_object "
 			       "structure\n");
@@ -636,7 +639,7 @@ static void add_scan_area(unsigned long ptr, unsigned long offset,
 		return;
 	}
 
-	area = kmem_cache_alloc(scan_area_cache, gfp & ~GFP_SLAB_BUG_MASK);
+	area = kmem_cache_alloc(scan_area_cache, gfp & GFP_KMEMLEAK_MASK);
 	if (!area) {
 		kmemleak_warn("kmemleak: Cannot allocate a scan area\n");
 		goto out;