linux-stable/include/linux/page-debug-flags.h
Akinobu Mita 6a11f75b6a 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>
2009-04-01 08:59:13 -07:00

30 lines
906 B
C

#ifndef LINUX_PAGE_DEBUG_FLAGS_H
#define LINUX_PAGE_DEBUG_FLAGS_H
/*
* page->debug_flags bits:
*
* PAGE_DEBUG_FLAG_POISON is set for poisoned pages. This is used to
* implement generic debug pagealloc feature. The pages are filled with
* poison patterns and set this flag after free_pages(). The poisoned
* pages are verified whether the patterns are not corrupted and clear
* the flag before alloc_pages().
*/
enum page_debug_flags {
PAGE_DEBUG_FLAG_POISON, /* Page is poisoned */
};
/*
* Ensure that CONFIG_WANT_PAGE_DEBUG_FLAGS reliably
* gets turned off when no debug features are enabling it!
*/
#ifdef CONFIG_WANT_PAGE_DEBUG_FLAGS
#if !defined(CONFIG_PAGE_POISONING) \
/* && !defined(CONFIG_PAGE_DEBUG_SOMETHING_ELSE) && ... */
#error WANT_PAGE_DEBUG_FLAGS is turned on with no debug features!
#endif
#endif /* CONFIG_WANT_PAGE_DEBUG_FLAGS */
#endif /* LINUX_PAGE_DEBUG_FLAGS_H */