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>
diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig
index c3ea215..cc12cd4 100644
--- a/arch/sparc/Kconfig
+++ b/arch/sparc/Kconfig
@@ -124,6 +124,9 @@
config OF
def_bool y
+config ARCH_SUPPORTS_DEBUG_PAGEALLOC
+ def_bool y if SPARC64
+
source "init/Kconfig"
source "kernel/Kconfig.freezer"
diff --git a/arch/sparc/Kconfig.debug b/arch/sparc/Kconfig.debug
index b8a15e2..d001b42 100644
--- a/arch/sparc/Kconfig.debug
+++ b/arch/sparc/Kconfig.debug
@@ -24,7 +24,8 @@
config DEBUG_PAGEALLOC
bool "Debug page memory allocations"
- depends on SPARC64 && DEBUG_KERNEL && !HIBERNATION
+ depends on DEBUG_KERNEL && !HIBERNATION
+ depends on ARCH_SUPPORTS_DEBUG_PAGEALLOC
help
Unmap pages from the kernel linear mapping after free_pages().
This results in a large slowdown, but helps to find certain types