diff options
| -rw-r--r-- | Documentation/kernel-parameters.txt | 5 | ||||
| -rw-r--r-- | Documentation/sysctl/kernel.txt | 12 | ||||
| -rw-r--r-- | include/linux/nmi.h | 1 | ||||
| -rw-r--r-- | kernel/sysctl.c | 9 | ||||
| -rw-r--r-- | kernel/watchdog.c | 33 |
5 files changed, 55 insertions, 5 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 6263a2da3e2f..0231f4508abe 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -1269,6 +1269,11 @@ bytes respectively. Such letter suffixes can also be entirely omitted. Format: <unsigned int> such that (rxsize & ~0x1fffc0) == 0. Default: 1024 + hardlockup_all_cpu_backtrace= + [KNL] Should the hard-lockup detector generate + backtraces on all cpus. + Format: <integer> + hashdist= [KNL,NUMA] Large hashes allocated during boot are distributed across NUMA nodes. Defaults on for 64-bit NUMA, off otherwise. diff --git a/Documentation/sysctl/kernel.txt b/Documentation/sysctl/kernel.txt index 6fccb69c03e7..af70d1541d3a 100644 --- a/Documentation/sysctl/kernel.txt +++ b/Documentation/sysctl/kernel.txt @@ -33,6 +33,7 @@ show up in /proc/sys/kernel: - domainname - hostname - hotplug +- hardlockup_all_cpu_backtrace - hung_task_panic - hung_task_check_count - hung_task_timeout_secs @@ -293,6 +294,17 @@ domain names are in general different. For a detailed discussion see the hostname(1) man page. ============================================================== +hardlockup_all_cpu_backtrace: + +This value controls the hard lockup detector behavior when a hard +lockup condition is detected as to whether or not to gather further +debug information. If enabled, arch-specific all-CPU stack dumping +will be initiated. + +0: do nothing. This is the default behavior. + +1: on detection capture more debug information. +============================================================== hotplug: diff --git a/include/linux/nmi.h b/include/linux/nmi.h index 78488e099ce7..7ec5b86735f3 100644 --- a/include/linux/nmi.h +++ b/include/linux/nmi.h @@ -73,6 +73,7 @@ extern int watchdog_user_enabled; extern int watchdog_thresh; extern unsigned long *watchdog_cpumask_bits; extern int sysctl_softlockup_all_cpu_backtrace; +extern int sysctl_hardlockup_all_cpu_backtrace; struct ctl_table; extern int proc_watchdog(struct ctl_table *, int , void __user *, size_t *, loff_t *); diff --git a/kernel/sysctl.c b/kernel/sysctl.c index 96c856b04081..1a5faa3e1521 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -898,6 +898,15 @@ static struct ctl_table kern_table[] = { .extra1 = &zero, .extra2 = &one, }, + { + .procname = "hardlockup_all_cpu_backtrace", + .data = &sysctl_hardlockup_all_cpu_backtrace, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_dointvec_minmax, + .extra1 = &zero, + .extra2 = &one, + }, #endif /* CONFIG_SMP */ #endif #if defined(CONFIG_X86_LOCAL_APIC) && defined(CONFIG_X86) diff --git a/kernel/watchdog.c b/kernel/watchdog.c index 452e4ed507e5..f6b32b8cbffe 100644 --- a/kernel/watchdog.c +++ b/kernel/watchdog.c @@ -57,8 +57,10 @@ int __read_mostly watchdog_thresh = 10; #ifdef CONFIG_SMP int __read_mostly sysctl_softlockup_all_cpu_backtrace; +int __read_mostly sysctl_hardlockup_all_cpu_backtrace; #else #define sysctl_softlockup_all_cpu_backtrace 0 +#define sysctl_hardlockup_all_cpu_backtrace 0 #endif static struct cpumask watchdog_cpumask __read_mostly; unsigned long *watchdog_cpumask_bits = cpumask_bits(&watchdog_cpumask); @@ -112,6 +114,7 @@ static unsigned long soft_lockup_nmi_warn; #ifdef CONFIG_HARDLOCKUP_DETECTOR static int hardlockup_panic = CONFIG_BOOTPARAM_HARDLOCKUP_PANIC_VALUE; +static unsigned long hardlockup_allcpu_dumped; /* * We may not want to enable hard lockup detection by default in all cases, * for example when running the kernel as a guest on a hypervisor. In these @@ -173,6 +176,13 @@ static int __init softlockup_all_cpu_backtrace_setup(char *str) return 1; } __setup("softlockup_all_cpu_backtrace=", softlockup_all_cpu_backtrace_setup); +static int __init hardlockup_all_cpu_backtrace_setup(char *str) +{ + sysctl_hardlockup_all_cpu_backtrace = + !!simple_strtol(str, NULL, 0); + return 1; +} +__setup("hardlockup_all_cpu_backtrace=", hardlockup_all_cpu_backtrace_setup); #endif /* @@ -318,17 +328,30 @@ static void watchdog_overflow_callback(struct perf_event *event, */ if (is_hardlockup()) { int this_cpu = smp_processor_id(); + struct pt_regs *regs = get_irq_regs(); /* only print hardlockups once */ if (__this_cpu_read(hard_watchdog_warn) == true) return; - if (hardlockup_panic) - panic("Watchdog detected hard LOCKUP on cpu %d", - this_cpu); + pr_emerg("Watchdog detected hard LOCKUP on cpu %d", this_cpu); + print_modules(); + print_irqtrace_events(current); + if (regs) + show_regs(regs); else - WARN(1, "Watchdog detected hard LOCKUP on cpu %d", - this_cpu); + dump_stack(); + + /* + * Perform all-CPU dump only once to avoid multiple hardlockups + * generating interleaving traces + */ + if (sysctl_hardlockup_all_cpu_backtrace && + !test_and_set_bit(0, &hardlockup_allcpu_dumped)) + trigger_allbutself_cpu_backtrace(); + + if (hardlockup_panic) + panic("Hard LOCKUP"); __this_cpu_write(hard_watchdog_warn, true); return; |
