x86: Check stack overflow in detail

Currently, only kernel stack is checked for the overflow, which
is not sufficient for systems that need a high reliability. To
enhance it, it is required to check the IRQ and exception
stacks, as well.

This patch checks all the stack types and will cause messages of
stacks in detail when free stack space drops below a certain
limit except user stack.

Signed-off-by: Mitsuo Hayasaka <mitsuo.hayasaka.hu@hitachi.com>
Cc: yrl.pp-manager.tt@hitachi.com
Cc: Randy Dunlap <rdunlap@xenotime.net>
Link: http://lkml.kernel.org/r/20111129060829.11076.51733.stgit@ltc219.sdl.hitachi.co.jp
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>

1 files changed, 5 insertions, 2 deletions

diff --git a/arch/x86/Kconfig.debug b/arch/x86/Kconfig.debug
index bf56e1793272..4caec1261f12 100644
--- a/arch/x86/Kconfig.debug
+++ b/arch/x86/Kconfig.debug
@@ -63,8 +63,11 @@ config DEBUG_STACKOVERFLOW
         bool "Check for stack overflows"
         depends on DEBUG_KERNEL
         ---help---
-          This option will cause messages to be printed if free stack space
-          drops below a certain limit.
+          Say Y here if you want to check the overflows of kernel, IRQ
+          and exception stacks. This option will cause messages of the
+          stacks in detail when free stack space drops below a certain
+          limit.
+          If in doubt, say "N".
 
 config X86_PTDUMP
         bool "Export kernel pagetable layout to userspace via debugfs"