diff options
Diffstat (limited to 'kernel/watchdog_hld.c')
| -rw-r--r-- | kernel/watchdog_hld.c | 16 |
1 files changed, 11 insertions, 5 deletions
diff --git a/kernel/watchdog_hld.c b/kernel/watchdog_hld.c index 71a62ceacdc8..e449a23e9d59 100644 --- a/kernel/watchdog_hld.c +++ b/kernel/watchdog_hld.c @@ -1,3 +1,4 @@ +// SPDX-License-Identifier: GPL-2.0 /* * Detect hard lockups on a system * @@ -12,6 +13,7 @@ #define pr_fmt(fmt) "NMI watchdog: " fmt #include <linux/nmi.h> +#include <linux/atomic.h> #include <linux/module.h> #include <linux/sched/debug.h> @@ -21,10 +23,11 @@ static DEFINE_PER_CPU(bool, hard_watchdog_warn); static DEFINE_PER_CPU(bool, watchdog_nmi_touch); static DEFINE_PER_CPU(struct perf_event *, watchdog_ev); +static DEFINE_PER_CPU(struct perf_event *, dead_event); static struct cpumask dead_events_mask; static unsigned long hardlockup_allcpu_dumped; -static unsigned int watchdog_cpus; +static atomic_t watchdog_cpus = ATOMIC_INIT(0); void arch_touch_nmi_watchdog(void) { @@ -188,7 +191,8 @@ void hardlockup_detector_perf_enable(void) if (hardlockup_detector_event_create()) return; - if (!watchdog_cpus++) + /* use original value for check */ + if (!atomic_fetch_inc(&watchdog_cpus)) pr_info("Enabled. Permanently consumes one hw-PMU counter.\n"); perf_event_enable(this_cpu_read(watchdog_ev)); @@ -203,8 +207,10 @@ void hardlockup_detector_perf_disable(void) if (event) { perf_event_disable(event); + this_cpu_write(watchdog_ev, NULL); + this_cpu_write(dead_event, event); cpumask_set_cpu(smp_processor_id(), &dead_events_mask); - watchdog_cpus--; + atomic_dec(&watchdog_cpus); } } @@ -218,7 +224,7 @@ void hardlockup_detector_perf_cleanup(void) int cpu; for_each_cpu(cpu, &dead_events_mask) { - struct perf_event *event = per_cpu(watchdog_ev, cpu); + struct perf_event *event = per_cpu(dead_event, cpu); /* * Required because for_each_cpu() reports unconditionally @@ -226,7 +232,7 @@ void hardlockup_detector_perf_cleanup(void) */ if (event) perf_event_release_kernel(event); - per_cpu(watchdog_ev, cpu) = NULL; + per_cpu(dead_event, cpu) = NULL; } cpumask_clear(&dead_events_mask); } |