From: Kurt Garloff <garloff@suse.de>
Subject: [PATCH] X86: sysctl to allow panic on IOCK NMI error
References: bnc427979

This patch introduces a sysctl /proc/sys/kernel/panic_on_io_nmi.,
which defaults to 0 (off).
When enabled, the kernel panics when the kernel receives an NMI
caused by an IO error.

The IO error triggered NMI indicates a serious system condition,
which could result in IO data corruption. Rather than contiuing,
panicing and dumping might be a better choice, so one can figure
out what's causing the IO error.
This could be especially important to companies running IO intensive
applications where corruption must be avoided, e.g. a banks databases.


Signed-off-by: Roberto Angelino <robertangelino@gmail.com>


Automatically created from "patches.suse/panic-on-io-nmi.diff" by xen-port-patches.py

Index: head-2008-11-25/arch/x86/kernel/traps_32-xen.c
===================================================================
--- head-2008-11-25.orig/arch/x86/kernel/traps_32-xen.c	2008-11-25 12:57:05.000000000 +0100
+++ head-2008-11-25/arch/x86/kernel/traps_32-xen.c	2008-11-25 13:13:12.000000000 +0100
@@ -83,6 +83,7 @@ gate_desc idt_table[256]
 #endif
 
 int panic_on_unrecovered_nmi;
+int panic_on_io_nmi;
 int kstack_depth_to_print = 24;
 static unsigned int code_bytes = 64;
 static int ignore_nmis;
@@ -670,6 +671,9 @@ io_check_error(unsigned char reason, str
 	printk(KERN_EMERG "NMI: IOCK error (debug interrupt?)\n");
 	show_registers(regs);
 
+	if (panic_on_io_nmi)
+		panic("NMI IOCK error: Not continuing");
+
 	/* Re-enable the IOCK line, wait for a few seconds */
 	clear_io_check_error(reason);
 }
Index: head-2008-11-25/arch/x86/kernel/traps_64-xen.c
===================================================================
--- head-2008-11-25.orig/arch/x86/kernel/traps_64-xen.c	2008-11-25 12:57:05.000000000 +0100
+++ head-2008-11-25/arch/x86/kernel/traps_64-xen.c	2008-11-25 13:13:12.000000000 +0100
@@ -56,6 +56,7 @@
 #include <mach_traps.h>
 
 int panic_on_unrecovered_nmi;
+int panic_on_io_nmi;
 int kstack_depth_to_print = 12;
 static unsigned int code_bytes = 64;
 static int ignore_nmis;
@@ -772,6 +773,9 @@ io_check_error(unsigned char reason, str
 	printk("NMI: IOCK error (debug interrupt?)\n");
 	show_registers(regs);
 
+	if (panic_on_io_nmi)
+		panic("NMI IOCK error: Not continuing");
+
 	/* Re-enable the IOCK line, wait for a few seconds */
 	clear_io_check_error(reason);
 }