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Commit 5211a242 authored by Kurt Garloff's avatar Kurt Garloff Committed by Ingo Molnar
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x86: Add sysctl to allow panic on IOCK NMI error 



This patch introduces a new 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
bank's databases.

[ SuSE has been shipping it for a while, it was done at the
  request of a large database vendor, for their users. ]

Signed-off-by: default avatarKurt Garloff <garloff@suse.de>
Signed-off-by: default avatarRoberto Angelino <robertangelino@gmail.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
LKML-Reference: <20090624213211.GA11291@kroah.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 9c26f52b

arch/x86/kernel/dumpstack.c

+1 −0
Original line number Diff line number Diff line
@@ -22,6 +22,7 @@ 
#include "dumpstack.h"



int panic_on_unrecovered_nmi;

int panic_on_io_nmi;

unsigned int code_bytes = 64;

int kstack_depth_to_print = 3 * STACKSLOTS_PER_LINE;

static int die_counter;

arch/x86/kernel/traps.c

+3 −0
Original line number Diff line number Diff line
@@ -346,6 +346,9 @@ io_check_error(unsigned char reason, struct pt_regs *regs) 
	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 */

	reason = (reason & 0xf) | 8;

	outb(reason, 0x61);

include/linux/kernel.h

+1 −0
Original line number Diff line number Diff line
@@ -303,6 +303,7 @@ extern int oops_in_progress; /* If set, an oops, panic(), BUG() or die() is in 
extern int panic_timeout;

extern int panic_on_oops;

extern int panic_on_unrecovered_nmi;

extern int panic_on_io_nmi;

extern const char *print_tainted(void);

extern void add_taint(unsigned flag);

extern int test_taint(unsigned flag);

kernel/sysctl.c

+8 −0
Original line number Diff line number Diff line
@@ -743,6 +743,14 @@ static struct ctl_table kern_table[] = { 
		.mode		= 0644,

		.proc_handler	= &proc_dointvec,

	},

	{

		.ctl_name	= CTL_UNNUMBERED,

		.procname	= "panic_on_io_nmi",

		.data		= &panic_on_io_nmi,

		.maxlen		= sizeof(int),

		.mode		= 0644,

		.proc_handler	= &proc_dointvec,

	},

	{

		.ctl_name	= KERN_BOOTLOADER_TYPE,

		.procname	= "bootloader_type",