diff options
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/Makefile | 1 | ||||
| -rw-r--r-- | kernel/nmi_watchdog.c | 259 | ||||
| -rw-r--r-- | kernel/sysctl.c | 15 |
3 files changed, 274 insertions, 1 deletions
diff --git a/kernel/Makefile b/kernel/Makefile index a987aa1676b5..d5c30060ac14 100644 --- a/kernel/Makefile +++ b/kernel/Makefile @@ -77,6 +77,7 @@ obj-$(CONFIG_AUDIT_TREE) += audit_tree.o obj-$(CONFIG_KPROBES) += kprobes.o obj-$(CONFIG_KGDB) += kgdb.o obj-$(CONFIG_DETECT_SOFTLOCKUP) += softlockup.o +obj-$(CONFIG_NMI_WATCHDOG) += nmi_watchdog.o obj-$(CONFIG_DETECT_HUNG_TASK) += hung_task.o obj-$(CONFIG_GENERIC_HARDIRQS) += irq/ obj-$(CONFIG_SECCOMP) += seccomp.o diff --git a/kernel/nmi_watchdog.c b/kernel/nmi_watchdog.c new file mode 100644 index 000000000000..a79d211c30df --- /dev/null +++ b/kernel/nmi_watchdog.c @@ -0,0 +1,259 @@ +/* + * Detect Hard Lockups using the NMI + * + * started by Don Zickus, Copyright (C) 2010 Red Hat, Inc. + * + * this code detects hard lockups: incidents in where on a CPU + * the kernel does not respond to anything except NMI. + * + * Note: Most of this code is borrowed heavily from softlockup.c, + * so thanks to Ingo for the initial implementation. + * Some chunks also taken from arch/x86/kernel/apic/nmi.c, thanks + * to those contributors as well. + */ + +#include <linux/mm.h> +#include <linux/cpu.h> +#include <linux/nmi.h> +#include <linux/init.h> +#include <linux/delay.h> +#include <linux/freezer.h> +#include <linux/lockdep.h> +#include <linux/notifier.h> +#include <linux/module.h> +#include <linux/sysctl.h> + +#include <asm/irq_regs.h> +#include <linux/perf_event.h> + +static DEFINE_PER_CPU(struct perf_event *, nmi_watchdog_ev); +static DEFINE_PER_CPU(int, nmi_watchdog_touch); +static DEFINE_PER_CPU(long, alert_counter); + +static int panic_on_timeout; + +void touch_nmi_watchdog(void) +{ + __raw_get_cpu_var(nmi_watchdog_touch) = 1; + touch_softlockup_watchdog(); +} +EXPORT_SYMBOL(touch_nmi_watchdog); + +void touch_all_nmi_watchdog(void) +{ + int cpu; + + for_each_online_cpu(cpu) + per_cpu(nmi_watchdog_touch, cpu) = 1; + touch_softlockup_watchdog(); +} + +static int __init setup_nmi_watchdog(char *str) +{ + if (!strncmp(str, "panic", 5)) { + panic_on_timeout = 1; + str = strchr(str, ','); + if (!str) + return 1; + ++str; + } + return 1; +} +__setup("nmi_watchdog=", setup_nmi_watchdog); + +struct perf_event_attr wd_hw_attr = { + .type = PERF_TYPE_HARDWARE, + .config = PERF_COUNT_HW_CPU_CYCLES, + .size = sizeof(struct perf_event_attr), + .pinned = 1, + .disabled = 1, +}; + +struct perf_event_attr wd_sw_attr = { + .type = PERF_TYPE_SOFTWARE, + .config = PERF_COUNT_SW_CPU_CLOCK, + .size = sizeof(struct perf_event_attr), + .pinned = 1, + .disabled = 1, +}; + +void wd_overflow(struct perf_event *event, int nmi, + struct perf_sample_data *data, + struct pt_regs *regs) +{ + int cpu = smp_processor_id(); + int touched = 0; + + if (__get_cpu_var(nmi_watchdog_touch)) { + per_cpu(nmi_watchdog_touch, cpu) = 0; + touched = 1; + } + + /* check to see if the cpu is doing anything */ + if (!touched && hw_nmi_is_cpu_stuck(regs)) { + /* + * Ayiee, looks like this CPU is stuck ... + * wait a few IRQs (5 seconds) before doing the oops ... + */ + per_cpu(alert_counter, cpu) += 1; + if (per_cpu(alert_counter, cpu) == 5) { + if (panic_on_timeout) + panic("NMI Watchdog detected LOCKUP on cpu %d", cpu); + else + WARN(1, "NMI Watchdog detected LOCKUP on cpu %d", cpu); + } + } else { + per_cpu(alert_counter, cpu) = 0; + } + + return; +} + +static int enable_nmi_watchdog(int cpu) +{ + struct perf_event *event; + struct perf_event_attr *wd_attr; + + event = per_cpu(nmi_watchdog_ev, cpu); + if (event && event->state > PERF_EVENT_STATE_OFF) + return 0; + + if (event == NULL) { + /* Try to register using hardware perf events first */ + wd_attr = &wd_hw_attr; + wd_attr->sample_period = hw_nmi_get_sample_period(); + event = perf_event_create_kernel_counter(wd_attr, cpu, -1, wd_overflow); + if (IS_ERR(event)) { + /* hardware doesn't exist or not supported, fallback to software events */ + printk(KERN_INFO "nmi_watchdog: hardware not available, trying software events\n"); + wd_attr = &wd_sw_attr; + wd_attr->sample_period = NSEC_PER_SEC; + event = perf_event_create_kernel_counter(wd_attr, cpu, -1, wd_overflow); + if (IS_ERR(event)) { + printk(KERN_ERR "nmi watchdog failed to create perf event on %i: %p\n", cpu, event); + return -1; + } + } + per_cpu(nmi_watchdog_ev, cpu) = event; + } + perf_event_enable(per_cpu(nmi_watchdog_ev, cpu)); + return 0; +} + +static void disable_nmi_watchdog(int cpu) +{ + struct perf_event *event; + + event = per_cpu(nmi_watchdog_ev, cpu); + if (event) { + perf_event_disable(per_cpu(nmi_watchdog_ev, cpu)); + per_cpu(nmi_watchdog_ev, cpu) = NULL; + perf_event_release_kernel(event); + } +} + +#ifdef CONFIG_SYSCTL +/* + * proc handler for /proc/sys/kernel/nmi_watchdog + */ +int nmi_watchdog_enabled; + +int proc_nmi_enabled(struct ctl_table *table, int write, + void __user *buffer, size_t *length, loff_t *ppos) +{ + int cpu; + + if (!write) { + struct perf_event *event; + for_each_online_cpu(cpu) { + event = per_cpu(nmi_watchdog_ev, cpu); + if (event && event->state > PERF_EVENT_STATE_OFF) { + nmi_watchdog_enabled = 1; + break; + } + } + proc_dointvec(table, write, buffer, length, ppos); + return 0; + } + + touch_all_nmi_watchdog(); + proc_dointvec(table, write, buffer, length, ppos); + if (nmi_watchdog_enabled) { + for_each_online_cpu(cpu) + if (enable_nmi_watchdog(cpu)) { + printk(KERN_ERR "NMI watchdog failed configuration, " + " can not be enabled\n"); + } + } else { + for_each_online_cpu(cpu) + disable_nmi_watchdog(cpu); + } + return 0; +} + +#endif /* CONFIG_SYSCTL */ + +/* + * Create/destroy watchdog threads as CPUs come and go: + */ +static int __cpuinit +cpu_callback(struct notifier_block *nfb, unsigned long action, void *hcpu) +{ + int hotcpu = (unsigned long)hcpu; + + switch (action) { + case CPU_UP_PREPARE: + case CPU_UP_PREPARE_FROZEN: + per_cpu(nmi_watchdog_touch, hotcpu) = 0; + break; + case CPU_ONLINE: + case CPU_ONLINE_FROZEN: + if (enable_nmi_watchdog(hotcpu)) + return NOTIFY_BAD; + break; +#ifdef CONFIG_HOTPLUG_CPU + case CPU_UP_CANCELED: + case CPU_UP_CANCELED_FROZEN: + disable_nmi_watchdog(hotcpu); + case CPU_DEAD: + case CPU_DEAD_FROZEN: + break; +#endif /* CONFIG_HOTPLUG_CPU */ + } + return NOTIFY_OK; +} + +static struct notifier_block __cpuinitdata cpu_nfb = { + .notifier_call = cpu_callback +}; + +static int __initdata nonmi_watchdog; + +static int __init nonmi_watchdog_setup(char *str) +{ + nonmi_watchdog = 1; + return 1; +} +__setup("nonmi_watchdog", nonmi_watchdog_setup); + +static int __init spawn_nmi_watchdog_task(void) +{ + void *cpu = (void *)(long)smp_processor_id(); + int err; + + if (nonmi_watchdog) + return 0; + + printk(KERN_INFO "NMI watchdog enabled, takes one hw-pmu counter.\n"); + + err = cpu_callback(&cpu_nfb, CPU_UP_PREPARE, cpu); + if (err == NOTIFY_BAD) { + BUG(); + return 1; + } + cpu_callback(&cpu_nfb, CPU_ONLINE, cpu); + register_cpu_notifier(&cpu_nfb); + + return 0; +} +early_initcall(spawn_nmi_watchdog_task); diff --git a/kernel/sysctl.c b/kernel/sysctl.c index 8686b0f5fc12..a38af430f0d8 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -74,6 +74,10 @@ #include <scsi/sg.h> #endif +#ifdef CONFIG_NMI_WATCHDOG +#include <linux/nmi.h> +#endif + #if defined(CONFIG_SYSCTL) @@ -682,7 +686,16 @@ static struct ctl_table kern_table[] = { .mode = 0444, .proc_handler = proc_dointvec, }, -#if defined(CONFIG_X86_LOCAL_APIC) && defined(CONFIG_X86) +#if defined(CONFIG_NMI_WATCHDOG) + { + .procname = "nmi_watchdog", + .data = &nmi_watchdog_enabled, + .maxlen = sizeof (int), + .mode = 0644, + .proc_handler = proc_nmi_enabled, + }, +#endif +#if defined(CONFIG_X86_LOCAL_APIC) && defined(CONFIG_X86) && !defined(CONFIG_NMI_WATCHDOG) { .procname = "unknown_nmi_panic", .data = &unknown_nmi_panic, |