---

yaml
---
r: 116653
b: refs/heads/master
c: a7b1374
h: refs/heads/master
i:
  116651: ae73c98
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 7a8e76a3829f1067b70f715771ff88baf2fbf3c3
+refs/heads/master: a7b1374333407f409cf8df7e623b12490f073c84

trunk/kernel/trace/ring_buffer.c

@@ -289,6 +289,12 @@ static void rb_free_cpu_buffer(struct ring_buffer_per_cpu *cpu_buffer)
 	kfree(cpu_buffer);
 }
 
+/*
+ * Causes compile errors if the struct buffer_page gets bigger
+ * than the struct page.
+ */
+extern int ring_buffer_page_too_big(void);
+
 /**
  * ring_buffer_alloc - allocate a new ring_buffer
  * @size: the size in bytes that is needed.
@@ -305,6 +311,11 @@ struct ring_buffer *ring_buffer_alloc(unsigned long size, unsigned flags)
 	int bsize;
 	int cpu;
 
+	/* Paranoid! Optimizes out when all is well */
+	if (sizeof(struct buffer_page) > sizeof(struct page))
+		ring_buffer_page_too_big();
+
+
 	/* keep it in its own cache line */
 	buffer = kzalloc(ALIGN(sizeof(*buffer), cache_line_size()),
 			 GFP_KERNEL);