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kernel/watchdog.c: add sysctl knob hardlockup_panic 

The only way to enable a hardlockup to panic the machine is to set
'nmi_watchdog=panic' on the kernel command line.

This makes it awkward for end users and folks who want to run automate
tests (like myself).

Mimic the softlockup_panic knob and create a /proc/sys/kernel/hardlockup_panic
knob.

Signed-off-by: Don Zickus <dzickus@redhat.com>
Cc: Ulrich Obergfell <uobergfe@redhat.com>
Acked-by: Jiri Kosina <jkosina@suse.cz>
Reviewed-by: Aaron Tomlin <atomlin@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Don Zickus 2015-11-05 18:44:44 -08:00 committed by Linus Torvalds
parent 55537871ef
commit ac1f591249
4 changed files with 16 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
Documentation/lockup-watchdogs.txt
View File

@ -20,8 +20,9 @@ kernel mode for more than 10 seconds (see "Implementation" below for
details), without letting other interrupts have a chance to run.
Similarly to the softlockup case, the current stack trace is displayed
upon detection and the system will stay locked up unless the default
behavior is changed, which can be done through a compile time knob,
"BOOTPARAM_HARDLOCKUP_PANIC", and a kernel parameter, "nmi_watchdog"
behavior is changed, which can be done through a sysctl,
'hardlockup_panic', a compile time knob, "BOOTPARAM_HARDLOCKUP_PANIC",
and a kernel parameter, "nmi_watchdog"
(see "Documentation/kernel-parameters.txt" for details).
The panic option can be used in combination with panic_timeout (this

1
include/linux/sched.h
View File

@ -384,6 +384,7 @@ extern int proc_dowatchdog_thresh(struct ctl_table *table, int write,
void __user *buffer,
size_t *lenp, loff_t *ppos);
extern unsigned int softlockup_panic;
extern unsigned int hardlockup_panic;
void lockup_detector_init(void);
#else
static inline void touch_softlockup_watchdog(void)

11
kernel/sysctl.c
View File

@ -888,6 +888,17 @@ static struct ctl_table kern_table[] = {
.extra1 = &zero,
.extra2 = &one,
},
#ifdef CONFIG_HARDLOCKUP_DETECTOR
{
.procname = "hardlockup_panic",
.data = &hardlockup_panic,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = &zero,
.extra2 = &one,
},
#endif
#ifdef CONFIG_SMP
{
.procname = "softlockup_all_cpu_backtrace",

2
kernel/watchdog.c
View File

@ -112,7 +112,7 @@ static unsigned long soft_lockup_nmi_warn;
* Should we panic when a soft-lockup or hard-lockup occurs:
*/
#ifdef CONFIG_HARDLOCKUP_DETECTOR
static int hardlockup_panic =
unsigned int __read_mostly hardlockup_panic =
CONFIG_BOOTPARAM_HARDLOCKUP_PANIC_VALUE;
static unsigned long hardlockup_allcpu_dumped;
/*