diff options
Diffstat (limited to 'kernel/watchdog.c')
| -rw-r--r-- | kernel/watchdog.c | 62 |
1 files changed, 51 insertions, 11 deletions
diff --git a/kernel/watchdog.c b/kernel/watchdog.c index 5b62d1002783..0685e3a8aa0a 100644 --- a/kernel/watchdog.c +++ b/kernel/watchdog.c @@ -25,6 +25,7 @@ #include <linux/stop_machine.h> #include <linux/sysctl.h> #include <linux/tick.h> +#include <linux/sys_info.h> #include <linux/sched/clock.h> #include <linux/sched/debug.h> @@ -65,6 +66,13 @@ int __read_mostly sysctl_hardlockup_all_cpu_backtrace; unsigned int __read_mostly hardlockup_panic = IS_ENABLED(CONFIG_BOOTPARAM_HARDLOCKUP_PANIC); +/* + * bitmasks to control what kinds of system info to be printed when + * hard lockup is detected, it could be task, memory, lock etc. + * Refer include/linux/sys_info.h for detailed bit definition. + */ +static unsigned long hardlockup_si_mask; + #ifdef CONFIG_SYSFS static unsigned int hardlockup_count; @@ -178,11 +186,15 @@ static void watchdog_hardlockup_kick(void) void watchdog_hardlockup_check(unsigned int cpu, struct pt_regs *regs) { + int hardlockup_all_cpu_backtrace; + if (per_cpu(watchdog_hardlockup_touched, cpu)) { per_cpu(watchdog_hardlockup_touched, cpu) = false; return; } + hardlockup_all_cpu_backtrace = (hardlockup_si_mask & SYS_INFO_ALL_BT) ? + 1 : sysctl_hardlockup_all_cpu_backtrace; /* * Check for a hardlockup by making sure the CPU's timer * interrupt is incrementing. The timer interrupt should have @@ -196,6 +208,15 @@ void watchdog_hardlockup_check(unsigned int cpu, struct pt_regs *regs) #ifdef CONFIG_SYSFS ++hardlockup_count; #endif + /* + * A poorly behaving BPF scheduler can trigger hard lockup by + * e.g. putting numerous affinitized tasks in a single queue and + * directing all CPUs at it. The following call can return true + * only once when sched_ext is enabled and will immediately + * abort the BPF scheduler and print out a warning message. + */ + if (scx_hardlockup(cpu)) + return; /* Only print hardlockups once. */ if (per_cpu(watchdog_hardlockup_warned, cpu)) @@ -205,7 +226,7 @@ void watchdog_hardlockup_check(unsigned int cpu, struct pt_regs *regs) * Prevent multiple hard-lockup reports if one cpu is already * engaged in dumping all cpu back traces. */ - if (sysctl_hardlockup_all_cpu_backtrace) { + if (hardlockup_all_cpu_backtrace) { if (test_and_set_bit_lock(0, &hard_lockup_nmi_warn)) return; } @@ -234,12 +255,13 @@ void watchdog_hardlockup_check(unsigned int cpu, struct pt_regs *regs) trigger_single_cpu_backtrace(cpu); } - if (sysctl_hardlockup_all_cpu_backtrace) { + if (hardlockup_all_cpu_backtrace) { trigger_allbutcpu_cpu_backtrace(cpu); if (!hardlockup_panic) clear_bit_unlock(0, &hard_lockup_nmi_warn); } + sys_info(hardlockup_si_mask & ~SYS_INFO_ALL_BT); if (hardlockup_panic) nmi_panic(regs, "Hard LOCKUP"); @@ -330,6 +352,13 @@ static void lockup_detector_update_enable(void) int __read_mostly sysctl_softlockup_all_cpu_backtrace; #endif +/* + * bitmasks to control what kinds of system info to be printed when + * soft lockup is detected, it could be task, memory, lock etc. + * Refer include/linux/sys_info.h for detailed bit definition. + */ +static unsigned long softlockup_si_mask; + static struct cpumask watchdog_allowed_mask __read_mostly; /* Global variables, exported for sysctl */ @@ -746,7 +775,7 @@ static enum hrtimer_restart watchdog_timer_fn(struct hrtimer *hrtimer) unsigned long touch_ts, period_ts, now; struct pt_regs *regs = get_irq_regs(); int duration; - int softlockup_all_cpu_backtrace = sysctl_softlockup_all_cpu_backtrace; + int softlockup_all_cpu_backtrace; unsigned long flags; if (!watchdog_enabled) @@ -758,6 +787,9 @@ static enum hrtimer_restart watchdog_timer_fn(struct hrtimer *hrtimer) if (panic_in_progress()) return HRTIMER_NORESTART; + softlockup_all_cpu_backtrace = (softlockup_si_mask & SYS_INFO_ALL_BT) ? + 1 : sysctl_softlockup_all_cpu_backtrace; + watchdog_hardlockup_kick(); /* kick the softlockup detector */ @@ -846,6 +878,7 @@ static enum hrtimer_restart watchdog_timer_fn(struct hrtimer *hrtimer) } add_taint(TAINT_SOFTLOCKUP, LOCKDEP_STILL_OK); + sys_info(softlockup_si_mask & ~SYS_INFO_ALL_BT); if (softlockup_panic) panic("softlockup: hung tasks"); } @@ -1197,6 +1230,13 @@ static const struct ctl_table watchdog_sysctls[] = { .extra1 = SYSCTL_ZERO, .extra2 = SYSCTL_ONE, }, + { + .procname = "softlockup_sys_info", + .data = &softlockup_si_mask, + .maxlen = sizeof(softlockup_si_mask), + .mode = 0644, + .proc_handler = sysctl_sys_info_handler, + }, #ifdef CONFIG_SMP { .procname = "softlockup_all_cpu_backtrace", @@ -1219,6 +1259,13 @@ static const struct ctl_table watchdog_sysctls[] = { .extra1 = SYSCTL_ZERO, .extra2 = SYSCTL_ONE, }, + { + .procname = "hardlockup_sys_info", + .data = &hardlockup_si_mask, + .maxlen = sizeof(hardlockup_si_mask), + .mode = 0644, + .proc_handler = sysctl_sys_info_handler, + }, #ifdef CONFIG_SMP { .procname = "hardlockup_all_cpu_backtrace", @@ -1231,14 +1278,11 @@ static const struct ctl_table watchdog_sysctls[] = { }, #endif /* CONFIG_SMP */ #endif -}; - -static struct ctl_table watchdog_hardlockup_sysctl[] = { { .procname = "nmi_watchdog", .data = &watchdog_hardlockup_user_enabled, .maxlen = sizeof(int), - .mode = 0444, + .mode = 0644, .proc_handler = proc_nmi_watchdog, .extra1 = SYSCTL_ZERO, .extra2 = SYSCTL_ONE, @@ -1248,10 +1292,6 @@ static struct ctl_table watchdog_hardlockup_sysctl[] = { static void __init watchdog_sysctl_init(void) { register_sysctl_init("kernel", watchdog_sysctls); - - if (watchdog_hardlockup_available) - watchdog_hardlockup_sysctl[0].mode = 0644; - register_sysctl_init("kernel", watchdog_hardlockup_sysctl); } #else |