diff options
| author | Akinobu Mita <akinobu.mita@gmail.com> | 2009-03-31 15:23:17 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-04-01 08:59:13 -0700 |
| commit | 6a11f75b6a17b5d9ac5025f8d048382fd1f47377 (patch) | |
| tree | a3415cd897823975b927f89a233d2703bf97ba2b /include | |
| parent | 610a77e04a8d9fe8764dc484e2182fa251ce1cc2 (diff) | |
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>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/mm_types.h | 4 | ||||
| -rw-r--r-- | include/linux/page-debug-flags.h | 30 | ||||
| -rw-r--r-- | include/linux/poison.h | 3 |
3 files changed, 37 insertions, 0 deletions
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index d84feb7bdbf0..ddadb4defe00 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 { diff --git a/include/linux/page-debug-flags.h b/include/linux/page-debug-flags.h new file mode 100644 index 000000000000..b0638fd91e92 --- /dev/null +++ b/include/linux/page-debug-flags.h @@ -0,0 +1,30 @@ +#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 */ diff --git a/include/linux/poison.h b/include/linux/poison.h index 9f31683728fd..6729f7dcd60e 100644 --- a/include/linux/poison.h +++ b/include/linux/poison.h @@ -17,6 +17,9 @@ */ #define TIMER_ENTRY_STATIC ((void *) 0x74737461) +/********** mm/debug-pagealloc.c **********/ +#define PAGE_POISON 0xaa + /********** mm/slab.c **********/ /* * Magic nums for obj red zoning. |