From 6a11f75b6a17b5d9ac5025f8d048382fd1f47377 Mon Sep 17 00:00:00 2001
From: Akinobu Mita <akinobu.mita@gmail.com>
Date: Tue, 31 Mar 2009 15:23:17 -0700
Subject: generic debug pagealloc

CONFIG_DEBUG_PAGEALLOC is now supported by x86, powerpc, sparc64, and
s390.  This patch implements it for the rest of the architectures by
filling the pages with poison byte patterns after free_pages() and
verifying the poison patterns before alloc_pages().

This generic one cannot detect invalid page accesses immediately but
invalid read access may cause invalid dereference by poisoned memory and
invalid write access can be detected after a long delay.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 include/linux/mm_types.h | 4 ++++
 1 file changed, 4 insertions(+)

(limited to 'include/linux/mm_types.h')

diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index d84feb7bdbf..ddadb4defe0 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -11,6 +11,7 @@
 #include <linux/rwsem.h>
 #include <linux/completion.h>
 #include <linux/cpumask.h>
+#include <linux/page-debug-flags.h>
 #include <asm/page.h>
 #include <asm/mmu.h>
 
@@ -174,6 +175,9 @@ struct vm_area_struct {
 #ifdef CONFIG_NUMA
 	struct mempolicy *vm_policy;	/* NUMA policy for the VMA */
 #endif
+#ifdef CONFIG_WANT_PAGE_DEBUG_FLAGS
+	unsigned long debug_flags;	/* Use atomic bitops on this */
+#endif
 };
 
 struct core_thread {
-- 
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