Messages in this thread Patch in this message |  | | From | Ben Zhang <> | Subject | [PATCH] watchdog: Add a sysctl to disable soft lockup detector | Date | Tue, 3 Dec 2013 13:54:34 -0800 |
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This provides usermode a way to disable only the soft lockup detector while keeping the hard lockup detector running.
kernel.softlockup_detector_enable=1: This is the default. The soft lockup detector is enabled. When a soft lockup is detected, a warning message with debug info is printed. The kernel may be configured to panics in this case via the sysctl kernel.softlockup_panic.
kernel.softlockup_detector_enable=0: The soft lockup detector is disabled. Warning message is not printed on soft lockup. The kernel does not panic on soft lockup regardless of the value of kernel.softlockup_panic. Note kernel.softlockup_detector_enable does not affect the hard lockup detector.
Signed-off-by: Ben Zhang <benzh@chromium.org> --- include/linux/sched.h | 1 + kernel/sysctl.c | 9 +++++++++ kernel/watchdog.c | 15 +++++++++++++++ 3 files changed, 25 insertions(+)
diff --git a/include/linux/sched.h b/include/linux/sched.h index 768b037..93ebec4 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -270,6 +270,7 @@ 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 softlockup_detector_enable; void lockup_detector_init(void); #else static inline void touch_softlockup_watchdog(void) diff --git a/kernel/sysctl.c b/kernel/sysctl.c index 34a6047..8ae1f36 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -840,6 +840,15 @@ static struct ctl_table kern_table[] = { .extra2 = &one, }, { + .procname = "softlockup_detector_enable", + .data = &softlockup_detector_enable, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_dointvec_minmax, + .extra1 = &zero, + .extra2 = &one, + }, + { .procname = "nmi_watchdog", .data = &watchdog_user_enabled, .maxlen = sizeof (int), diff --git a/kernel/watchdog.c b/kernel/watchdog.c index 4431610..b9594e6 100644 --- a/kernel/watchdog.c +++ b/kernel/watchdog.c @@ -80,6 +80,18 @@ static int __init softlockup_panic_setup(char *str) } __setup("softlockup_panic=", softlockup_panic_setup); +unsigned int __read_mostly softlockup_detector_enable = 1; + +static int __init softlockup_detector_enable_setup(char *str) +{ + unsigned long res; + if (kstrtoul(str, 0, &res)) + res = 1; + softlockup_detector_enable = res; + return 1; +} +__setup("softlockup_detector_enable=", softlockup_detector_enable_setup); + static int __init nowatchdog_setup(char *str) { watchdog_user_enabled = 0; @@ -293,6 +305,9 @@ static enum hrtimer_restart watchdog_timer_fn(struct hrtimer *hrtimer) return HRTIMER_RESTART; } + if (!softlockup_detector_enable) + return HRTIMER_RESTART; + /* check for a softlockup * This is done by making sure a high priority task is * being scheduled. The task touches the watchdog to -- 1.8.4.1
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