diff options
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/fork.c | 1 | ||||
| -rw-r--r-- | kernel/rcu/tree.c | 34 | ||||
| -rw-r--r-- | kernel/rcu/tree_exp.h | 3 | ||||
| -rw-r--r-- | kernel/time/clocksource.c | 25 | ||||
| -rw-r--r-- | kernel/time/tick-sched.c | 5 | ||||
| -rw-r--r-- | kernel/trace/tracing_map.c | 7 |
6 files changed, 70 insertions, 5 deletions
diff --git a/kernel/fork.c b/kernel/fork.c index 47ff3b35352e..0d944e92a43f 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -1748,6 +1748,7 @@ static int copy_fs(unsigned long clone_flags, struct task_struct *tsk) if (clone_flags & CLONE_FS) { /* tsk->fs is already what we want */ spin_lock(&fs->lock); + /* "users" and "in_exec" locked for check_unsafe_exec() */ if (fs->in_exec) { spin_unlock(&fs->lock); return -EAGAIN; diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 1ae851777806..b2bccfd37c38 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -1013,6 +1013,38 @@ static bool rcu_future_gp_cleanup(struct rcu_node *rnp) return needmore; } +static void swake_up_one_online_ipi(void *arg) +{ + struct swait_queue_head *wqh = arg; + + swake_up_one(wqh); +} + +static void swake_up_one_online(struct swait_queue_head *wqh) +{ + int cpu = get_cpu(); + + /* + * If called from rcutree_report_cpu_starting(), wake up + * is dangerous that late in the CPU-down hotplug process. The + * scheduler might queue an ignored hrtimer. Defer the wake up + * to an online CPU instead. + */ + if (unlikely(cpu_is_offline(cpu))) { + int target; + + target = cpumask_any_and(housekeeping_cpumask(HK_TYPE_RCU), + cpu_online_mask); + + smp_call_function_single(target, swake_up_one_online_ipi, + wqh, 0); + put_cpu(); + } else { + put_cpu(); + swake_up_one(wqh); + } +} + /* * Awaken the grace-period kthread. Don't do a self-awaken (unless in an * interrupt or softirq handler, in which case we just might immediately @@ -1037,7 +1069,7 @@ static void rcu_gp_kthread_wake(void) return; WRITE_ONCE(rcu_state.gp_wake_time, jiffies); WRITE_ONCE(rcu_state.gp_wake_seq, READ_ONCE(rcu_state.gp_seq)); - swake_up_one(&rcu_state.gp_wq); + swake_up_one_online(&rcu_state.gp_wq); } /* diff --git a/kernel/rcu/tree_exp.h b/kernel/rcu/tree_exp.h index 6d7cea5d591f..2ac440bc7e10 100644 --- a/kernel/rcu/tree_exp.h +++ b/kernel/rcu/tree_exp.h @@ -173,7 +173,6 @@ static bool sync_rcu_exp_done_unlocked(struct rcu_node *rnp) return ret; } - /* * Report the exit from RCU read-side critical section for the last task * that queued itself during or before the current expedited preemptible-RCU @@ -201,7 +200,7 @@ static void __rcu_report_exp_rnp(struct rcu_node *rnp, raw_spin_unlock_irqrestore_rcu_node(rnp, flags); if (wake) { smp_mb(); /* EGP done before wake_up(). */ - swake_up_one(&rcu_state.expedited_wq); + swake_up_one_online(&rcu_state.expedited_wq); } break; } diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c index c108ed8a9804..3052b1f1168e 100644 --- a/kernel/time/clocksource.c +++ b/kernel/time/clocksource.c @@ -99,6 +99,7 @@ static u64 suspend_start; * Interval: 0.5sec. */ #define WATCHDOG_INTERVAL (HZ >> 1) +#define WATCHDOG_INTERVAL_MAX_NS ((2 * WATCHDOG_INTERVAL) * (NSEC_PER_SEC / HZ)) /* * Threshold: 0.0312s, when doubled: 0.0625s. @@ -134,6 +135,7 @@ static DECLARE_WORK(watchdog_work, clocksource_watchdog_work); static DEFINE_SPINLOCK(watchdog_lock); static int watchdog_running; static atomic_t watchdog_reset_pending; +static int64_t watchdog_max_interval; static inline void clocksource_watchdog_lock(unsigned long *flags) { @@ -399,8 +401,8 @@ static inline void clocksource_reset_watchdog(void) static void clocksource_watchdog(struct timer_list *unused) { u64 csnow, wdnow, cslast, wdlast, delta; + int64_t wd_nsec, cs_nsec, interval; int next_cpu, reset_pending; - int64_t wd_nsec, cs_nsec; struct clocksource *cs; enum wd_read_status read_ret; unsigned long extra_wait = 0; @@ -470,6 +472,27 @@ static void clocksource_watchdog(struct timer_list *unused) if (atomic_read(&watchdog_reset_pending)) continue; + /* + * The processing of timer softirqs can get delayed (usually + * on account of ksoftirqd not getting to run in a timely + * manner), which causes the watchdog interval to stretch. + * Skew detection may fail for longer watchdog intervals + * on account of fixed margins being used. + * Some clocksources, e.g. acpi_pm, cannot tolerate + * watchdog intervals longer than a few seconds. + */ + interval = max(cs_nsec, wd_nsec); + if (unlikely(interval > WATCHDOG_INTERVAL_MAX_NS)) { + if (system_state > SYSTEM_SCHEDULING && + interval > 2 * watchdog_max_interval) { + watchdog_max_interval = interval; + pr_warn("Long readout interval, skipping watchdog check: cs_nsec: %lld wd_nsec: %lld\n", + cs_nsec, wd_nsec); + } + watchdog_timer.expires = jiffies; + continue; + } + /* Check the deviation from the watchdog clocksource. */ md = cs->uncertainty_margin + watchdog->uncertainty_margin; if (abs(cs_nsec - wd_nsec) > md) { diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index d2501673028d..01fb50c1b17e 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -1577,6 +1577,7 @@ void tick_cancel_sched_timer(int cpu) { struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu); ktime_t idle_sleeptime, iowait_sleeptime; + unsigned long idle_calls, idle_sleeps; # ifdef CONFIG_HIGH_RES_TIMERS if (ts->sched_timer.base) @@ -1585,9 +1586,13 @@ void tick_cancel_sched_timer(int cpu) idle_sleeptime = ts->idle_sleeptime; iowait_sleeptime = ts->iowait_sleeptime; + idle_calls = ts->idle_calls; + idle_sleeps = ts->idle_sleeps; memset(ts, 0, sizeof(*ts)); ts->idle_sleeptime = idle_sleeptime; ts->iowait_sleeptime = iowait_sleeptime; + ts->idle_calls = idle_calls; + ts->idle_sleeps = idle_sleeps; } #endif diff --git a/kernel/trace/tracing_map.c b/kernel/trace/tracing_map.c index c774e560f2f9..a4dcf0f24352 100644 --- a/kernel/trace/tracing_map.c +++ b/kernel/trace/tracing_map.c @@ -574,7 +574,12 @@ __tracing_map_insert(struct tracing_map *map, void *key, bool lookup_only) } memcpy(elt->key, key, map->key_size); - entry->val = elt; + /* + * Ensure the initialization is visible and + * publish the elt. + */ + smp_wmb(); + WRITE_ONCE(entry->val, elt); atomic64_inc(&map->hits); return entry->val; |