x86: Panic on detection of stack overflow

Currently, messages are just output on the detection of stack
overflow, which is not sufficient for systems that need a
high reliability. This is because in general the overflow may
corrupt data, and the additional corruption may occur due to
reading them unless systems stop.

This patch adds the sysctl parameter
kernel.panic_on_stackoverflow and causes a panic when detecting
the overflows of kernel, IRQ and exception stacks except user
stack according to the parameter. It is disabled by default.

Signed-off-by: Mitsuo Hayasaka <mitsuo.hayasaka.hu@hitachi.com>
Cc: yrl.pp-manager.tt@hitachi.com
Cc: Randy Dunlap <rdunlap@xenotime.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Link: http://lkml.kernel.org/r/20111129060836.11076.12323.stgit@ltc219.sdl.hitachi.co.jp
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 2 insertions, 0 deletions

diff --git a/arch/x86/kernel/irq_32.c b/arch/x86/kernel/irq_32.c
index 72090705a656..e16e99ebd7ad 100644
--- a/arch/x86/kernel/irq_32.c
+++ b/arch/x86/kernel/irq_32.c
@@ -43,6 +43,8 @@ static void print_stack_overflow(void)
 {
         printk(KERN_WARNING "low stack detected by irq handler\n");
         dump_stack();
+        if (sysctl_panic_on_stackoverflow)
+                panic("low stack detected by irq handler - check messages\n");
 }
 
 #else