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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: Kurt Garloff <garloff@suse.de>
Signed-off-by: Roberto Angelino <robertangelino@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
LKML-Reference: <20090624213211.GA11291@kroah.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Kurt Garloff 2009-06-24 14:32:11 -07:00 committed by Ingo Molnar
parent 9c26f52b90
commit 5211a242d0
4 changed files with 13 additions and 0 deletions
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1
arch/x86/kernel/dumpstack.c
View File

@ -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;

3
arch/x86/kernel/traps.c
View File

@ -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);

1
include/linux/kernel.h
View File

@ -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);

8
kernel/sysctl.c
View File

@ -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",