[ANNOUNCE] 3.12.54-rt73

From: Steven Rostedt
Date: Mon Feb 29 2016 - 12:06:21 EST


Dear RT Folks,

I'm pleased to announce the 3.12.54-rt73 stable release.


You can get this release via the git tree at:

git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-stable-rt.git

branch: v3.12-rt
Head SHA1: ca4a3e96670bf4ad6a49a9020513f7bb99ded08b


Or to build 3.12.54-rt73 directly, the following patches should be applied:

http://www.kernel.org/pub/linux/kernel/v3.x/linux-3.12.tar.xz

http://www.kernel.org/pub/linux/kernel/v3.x/patch-3.12.54.xz

http://www.kernel.org/pub/linux/kernel/projects/rt/3.12/patch-3.12.54-rt73.patch.xz



You can also build from 3.12.54-rt72 by applying the incremental patch:

http://www.kernel.org/pub/linux/kernel/projects/rt/3.12/incr/patch-3.12.54-rt72-rt73.patch.xz



Enjoy,

-- Steve


Changes from v3.12.54-rt72:

---

Grygorii Strashko (2):
ARM: smp: Move clear_tasks_mm_cpumask() call to __cpu_die()
net/core/cpuhotplug: Drain input_pkt_queue lockless

Josh Cartwright (1):
net: Make synchronize_rcu_expedited() conditional on !RT_FULL

Peter Zijlstra (1):
sched: Introduce the trace_sched_waking tracepoint

Sebastian Andrzej Siewior (2):
cpufreq: Remove cpufreq_rwsem
dump stack: don't disable preemption during trace

Steven Rostedt (Red Hat) (1):
Linux 3.12.54-rt73

Thomas Gleixner (2):
rtmutex: Handle non enqueued waiters gracefully
irqwork: Move irq safe work to irq context

bmouring@xxxxxx (1):
rtmutex: Use chainwalking control enum

----
arch/arm/kernel/smp.c | 5 ++--
arch/x86/kernel/dumpstack_64.c | 8 +++----
drivers/cpufreq/cpufreq.c | 49 ++++++---------------------------------
include/linux/irq_work.h | 6 +++++
include/trace/events/sched.h | 30 +++++++++++++++++-------
kernel/irq_work.c | 9 +++++++
kernel/rtmutex.c | 4 ++--
kernel/sched/core.c | 8 ++++---
kernel/timer.c | 6 ++---
kernel/trace/trace_sched_switch.c | 2 +-
kernel/trace/trace_sched_wakeup.c | 2 +-
lib/dump_stack.c | 4 ++--
localversion-rt | 2 +-
net/core/dev.c | 4 ++--
14 files changed, 66 insertions(+), 73 deletions(-)
---------------------------
diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
index bd1b9e633356..2f7325963bf5 100644
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c
@@ -207,8 +207,6 @@ int __cpu_disable(void)
flush_cache_louis();
local_flush_tlb_all();

- clear_tasks_mm_cpumask(cpu);
-
return 0;
}

@@ -224,6 +222,9 @@ void __cpu_die(unsigned int cpu)
pr_err("CPU%u: cpu didn't die\n", cpu);
return;
}
+
+ clear_tasks_mm_cpumask(cpu);
+
printk(KERN_NOTICE "CPU%u: shutdown\n", cpu);

/*
diff --git a/arch/x86/kernel/dumpstack_64.c b/arch/x86/kernel/dumpstack_64.c
index 66e274a3d968..37aee503a7ba 100644
--- a/arch/x86/kernel/dumpstack_64.c
+++ b/arch/x86/kernel/dumpstack_64.c
@@ -114,7 +114,7 @@ void dump_trace(struct task_struct *task, struct pt_regs *regs,
unsigned long *stack, unsigned long bp,
const struct stacktrace_ops *ops, void *data)
{
- const unsigned cpu = get_cpu();
+ const unsigned cpu = get_cpu_light();
unsigned long *irq_stack_end =
(unsigned long *)per_cpu(irq_stack_ptr, cpu);
unsigned used = 0;
@@ -191,7 +191,7 @@ void dump_trace(struct task_struct *task, struct pt_regs *regs,
* This handles the process stack:
*/
bp = ops->walk_stack(tinfo, stack, bp, ops, data, NULL, &graph);
- put_cpu();
+ put_cpu_light();
}
EXPORT_SYMBOL(dump_trace);

@@ -205,7 +205,7 @@ show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs,
int cpu;
int i;

- preempt_disable();
+ migrate_disable();
cpu = smp_processor_id();

irq_stack_end = (unsigned long *)(per_cpu(irq_stack_ptr, cpu));
@@ -238,7 +238,7 @@ show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs,
pr_cont(" %016lx", *stack++);
touch_nmi_watchdog();
}
- preempt_enable();
+ migrate_enable();

pr_cont("\n");
show_trace_log_lvl(task, regs, sp, bp, log_lvl);
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 8356b481e339..012d5169eee2 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -90,12 +90,6 @@ static void unlock_policy_rwsem_##mode(int cpu) \
unlock_policy_rwsem(read, cpu);
unlock_policy_rwsem(write, cpu);

-/*
- * rwsem to guarantee that cpufreq driver module doesn't unload during critical
- * sections
- */
-static DECLARE_RWSEM(cpufreq_rwsem);
-
/* internal prototypes */
static int __cpufreq_governor(struct cpufreq_policy *policy,
unsigned int event);
@@ -191,9 +185,6 @@ struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu)
if (cpufreq_disabled() || (cpu >= nr_cpu_ids))
return NULL;

- if (!down_read_trylock(&cpufreq_rwsem))
- return NULL;
-
/* get the cpufreq driver */
read_lock_irqsave(&cpufreq_driver_lock, flags);

@@ -206,9 +197,6 @@ struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu)

read_unlock_irqrestore(&cpufreq_driver_lock, flags);

- if (!policy)
- up_read(&cpufreq_rwsem);
-
return policy;
}
EXPORT_SYMBOL_GPL(cpufreq_cpu_get);
@@ -219,7 +207,6 @@ void cpufreq_cpu_put(struct cpufreq_policy *policy)
return;

kobject_put(&policy->kobj);
- up_read(&cpufreq_rwsem);
}
EXPORT_SYMBOL_GPL(cpufreq_cpu_put);

@@ -664,13 +651,10 @@ static ssize_t show(struct kobject *kobj, struct attribute *attr, char *buf)
{
struct cpufreq_policy *policy = to_policy(kobj);
struct freq_attr *fattr = to_attr(attr);
- ssize_t ret = -EINVAL;
-
- if (!down_read_trylock(&cpufreq_rwsem))
- goto exit;
+ ssize_t ret;

if (lock_policy_rwsem_read(policy->cpu) < 0)
- goto up_read;
+ return -EINVAL;

if (fattr->show)
ret = fattr->show(policy, buf);
@@ -679,9 +663,6 @@ static ssize_t show(struct kobject *kobj, struct attribute *attr, char *buf)

unlock_policy_rwsem_read(policy->cpu);

-up_read:
- up_read(&cpufreq_rwsem);
-exit:
return ret;
}

@@ -697,11 +678,8 @@ static ssize_t store(struct kobject *kobj, struct attribute *attr,
if (!cpu_online(policy->cpu))
goto unlock;

- if (!down_read_trylock(&cpufreq_rwsem))
- goto unlock;
-
if (lock_policy_rwsem_write(policy->cpu) < 0)
- goto up_read;
+ goto unlock;

if (fattr->store)
ret = fattr->store(policy, buf, count);
@@ -710,8 +688,6 @@ static ssize_t store(struct kobject *kobj, struct attribute *attr,

unlock_policy_rwsem_write(policy->cpu);

-up_read:
- up_read(&cpufreq_rwsem);
unlock:
put_online_cpus();

@@ -1011,9 +987,6 @@ static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif,
}
#endif

- if (!down_read_trylock(&cpufreq_rwsem))
- return 0;
-
#ifdef CONFIG_HOTPLUG_CPU
/* Check if this cpu was hot-unplugged earlier and has siblings */
read_lock_irqsave(&cpufreq_driver_lock, flags);
@@ -1021,7 +994,6 @@ static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif,
if (cpumask_test_cpu(cpu, tpolicy->related_cpus)) {
read_unlock_irqrestore(&cpufreq_driver_lock, flags);
ret = cpufreq_add_policy_cpu(tpolicy, cpu, dev, frozen);
- up_read(&cpufreq_rwsem);
return ret;
}
}
@@ -1035,7 +1007,7 @@ static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif,
policy = cpufreq_policy_alloc();

if (!policy)
- goto nomem_out;
+ return ret;


/*
@@ -1106,7 +1078,6 @@ static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif,
cpufreq_init_policy(policy);

kobject_uevent(&policy->kobj, KOBJ_ADD);
- up_read(&cpufreq_rwsem);

pr_debug("initialization complete\n");

@@ -1120,8 +1091,6 @@ err_out_unregister:

err_set_policy_cpu:
cpufreq_policy_free(policy);
-nomem_out:
- up_read(&cpufreq_rwsem);

return ret;
}
@@ -1474,9 +1443,6 @@ unsigned int cpufreq_get(unsigned int cpu)
if (cpufreq_disabled() || !cpufreq_driver)
return -ENOENT;

- if (!down_read_trylock(&cpufreq_rwsem))
- return 0;
-
if (unlikely(lock_policy_rwsem_read(cpu)))
goto out_policy;

@@ -1485,8 +1451,6 @@ unsigned int cpufreq_get(unsigned int cpu)
unlock_policy_rwsem_read(cpu);

out_policy:
- up_read(&cpufreq_rwsem);
-
return ret_freq;
}
EXPORT_SYMBOL(cpufreq_get);
@@ -2184,16 +2148,17 @@ int cpufreq_unregister_driver(struct cpufreq_driver *driver)

pr_debug("unregistering driver %s\n", driver->name);

+ /* Protect against concurrent cpu hotplug */
+ get_online_cpus();
subsys_interface_unregister(&cpufreq_interface);
unregister_hotcpu_notifier(&cpufreq_cpu_notifier);

- down_write(&cpufreq_rwsem);
write_lock_irqsave(&cpufreq_driver_lock, flags);

cpufreq_driver = NULL;

write_unlock_irqrestore(&cpufreq_driver_lock, flags);
- up_write(&cpufreq_rwsem);
+ put_online_cpus();

return 0;
}
diff --git a/include/linux/irq_work.h b/include/linux/irq_work.h
index 4a8c7a2df480..ccd736ebee9e 100644
--- a/include/linux/irq_work.h
+++ b/include/linux/irq_work.h
@@ -44,4 +44,10 @@ bool irq_work_needs_cpu(void);
static inline bool irq_work_needs_cpu(void) { return false; }
#endif

+#if defined(CONFIG_IRQ_WORK) && defined(CONFIG_PREEMPT_RT_FULL)
+void irq_work_tick_soft(void);
+#else
+static inline void irq_work_tick_soft(void) { }
+#endif
+
#endif /* _LINUX_IRQ_WORK_H */
diff --git a/include/trace/events/sched.h b/include/trace/events/sched.h
index 2e7d9947a10d..004eb037865c 100644
--- a/include/trace/events/sched.h
+++ b/include/trace/events/sched.h
@@ -55,9 +55,9 @@ TRACE_EVENT(sched_kthread_stop_ret,
*/
DECLARE_EVENT_CLASS(sched_wakeup_template,

- TP_PROTO(struct task_struct *p, int success),
+ TP_PROTO(struct task_struct *p),

- TP_ARGS(__perf_task(p), success),
+ TP_ARGS(__perf_task(p)),

TP_STRUCT__entry(
__array( char, comm, TASK_COMM_LEN )
@@ -71,25 +71,37 @@ DECLARE_EVENT_CLASS(sched_wakeup_template,
memcpy(__entry->comm, p->comm, TASK_COMM_LEN);
__entry->pid = p->pid;
__entry->prio = p->prio;
- __entry->success = success;
+ __entry->success = 1; /* rudiment, kill when possible */
__entry->target_cpu = task_cpu(p);
),

- TP_printk("comm=%s pid=%d prio=%d success=%d target_cpu=%03d",
+ TP_printk("comm=%s pid=%d prio=%d target_cpu=%03d",
__entry->comm, __entry->pid, __entry->prio,
- __entry->success, __entry->target_cpu)
+ __entry->target_cpu)
);

+/*
+ * Tracepoint called when waking a task; this tracepoint is guaranteed to be
+ * called from the waking context.
+ */
+DEFINE_EVENT(sched_wakeup_template, sched_waking,
+ TP_PROTO(struct task_struct *p),
+ TP_ARGS(p));
+
+/*
+ * Tracepoint called when the task is actually woken; p->state == TASK_RUNNNG.
+ * It it not always called from the waking context.
+ */
DEFINE_EVENT(sched_wakeup_template, sched_wakeup,
- TP_PROTO(struct task_struct *p, int success),
- TP_ARGS(p, success));
+ TP_PROTO(struct task_struct *p),
+ TP_ARGS(p));

/*
* Tracepoint for waking up a new task:
*/
DEFINE_EVENT(sched_wakeup_template, sched_wakeup_new,
- TP_PROTO(struct task_struct *p, int success),
- TP_ARGS(p, success));
+ TP_PROTO(struct task_struct *p),
+ TP_ARGS(p));

#ifdef CREATE_TRACE_POINTS
static inline long __trace_sched_switch_state(struct task_struct *p)
diff --git a/kernel/irq_work.c b/kernel/irq_work.c
index af8ceafc94e4..883bb73698b9 100644
--- a/kernel/irq_work.c
+++ b/kernel/irq_work.c
@@ -163,8 +163,17 @@ void irq_work_tick(void)

if (!llist_empty(raised) && !arch_irq_work_has_interrupt())
irq_work_run_list(raised);
+
+ if (!IS_ENABLED(CONFIG_PREEMPT_RT_FULL))
+ irq_work_run_list(this_cpu_ptr(&lazy_list));
+}
+
+#if defined(CONFIG_IRQ_WORK) && defined(CONFIG_PREEMPT_RT_FULL)
+void irq_work_tick_soft(void)
+{
irq_work_run_list(this_cpu_ptr(&lazy_list));
}
+#endif

/*
* Synchronize against the irq_work @entry, ensures the entry is not
diff --git a/kernel/rtmutex.c b/kernel/rtmutex.c
index 7601c1332a88..8061201b3163 100644
--- a/kernel/rtmutex.c
+++ b/kernel/rtmutex.c
@@ -1182,7 +1182,7 @@ static void noinline __sched rt_spin_lock_slowlock(struct rt_mutex *lock)
__set_current_state(TASK_UNINTERRUPTIBLE);
pi_unlock(&self->pi_lock);

- ret = task_blocks_on_rt_mutex(lock, &waiter, self, 0);
+ ret = task_blocks_on_rt_mutex(lock, &waiter, self, RT_MUTEX_MIN_CHAINWALK);
BUG_ON(ret);

for (;;) {
@@ -2065,7 +2065,7 @@ int rt_mutex_start_proxy_lock(struct rt_mutex *lock,
ret = 0;
}

- if (unlikely(ret))
+ if (ret && rt_mutex_has_waiters(lock))
remove_waiter(lock, waiter);

raw_spin_unlock(&lock->wait_lock);
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 3e8b790e5c17..14b5ba66fa72 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -1394,9 +1394,9 @@ static void
ttwu_do_wakeup(struct rq *rq, struct task_struct *p, int wake_flags)
{
check_preempt_curr(rq, p, wake_flags);
- trace_sched_wakeup(p, true);
-
p->state = TASK_RUNNING;
+ trace_sched_wakeup(p);
+
#ifdef CONFIG_SMP
if (p->sched_class->task_woken)
p->sched_class->task_woken(rq, p);
@@ -1581,6 +1581,8 @@ try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags)
if (!(wake_flags & WF_LOCK_SLEEPER))
p->saved_state = TASK_RUNNING;

+ trace_sched_waking(p);
+
success = 1; /* we're going to change ->state */
cpu = task_cpu(p);

@@ -1826,7 +1828,7 @@ void wake_up_new_task(struct task_struct *p)
rq = __task_rq_lock(p);
activate_task(rq, p, 0);
p->on_rq = 1;
- trace_sched_wakeup_new(p, true);
+ trace_sched_wakeup_new(p);
check_preempt_curr(rq, p, WF_FORK);
#ifdef CONFIG_SMP
if (p->sched_class->task_woken)
diff --git a/kernel/timer.c b/kernel/timer.c
index bf1277c2203b..400ef0bde253 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -1450,7 +1450,7 @@ void update_process_times(int user_tick)
scheduler_tick();
run_local_timers();
rcu_check_callbacks(cpu, user_tick);
-#if defined(CONFIG_IRQ_WORK) && !defined(CONFIG_PREEMPT_RT_FULL)
+#if defined(CONFIG_IRQ_WORK)
if (in_irq())
irq_work_run();
#endif
@@ -1466,9 +1466,7 @@ static void run_timer_softirq(struct softirq_action *h)

hrtimer_run_pending();

-#if defined(CONFIG_IRQ_WORK) && defined(CONFIG_PREEMPT_RT_FULL)
- irq_work_tick();
-#endif
+ irq_work_tick_soft();

if (time_after_eq(jiffies, base->timer_jiffies))
__run_timers(base);
diff --git a/kernel/trace/trace_sched_switch.c b/kernel/trace/trace_sched_switch.c
index 4e98e3b257a3..82fe794af532 100644
--- a/kernel/trace/trace_sched_switch.c
+++ b/kernel/trace/trace_sched_switch.c
@@ -106,7 +106,7 @@ tracing_sched_wakeup_trace(struct trace_array *tr,
}

static void
-probe_sched_wakeup(void *ignore, struct task_struct *wakee, int success)
+probe_sched_wakeup(void *ignore, struct task_struct *wakee)
{
struct trace_array_cpu *data;
unsigned long flags;
diff --git a/kernel/trace/trace_sched_wakeup.c b/kernel/trace/trace_sched_wakeup.c
index fee77e15d815..8e967ca56006 100644
--- a/kernel/trace/trace_sched_wakeup.c
+++ b/kernel/trace/trace_sched_wakeup.c
@@ -458,7 +458,7 @@ static void wakeup_reset(struct trace_array *tr)
}

static void
-probe_wakeup(void *ignore, struct task_struct *p, int success)
+probe_wakeup(void *ignore, struct task_struct *p)
{
struct trace_array_cpu *data;
int cpu = smp_processor_id();
diff --git a/lib/dump_stack.c b/lib/dump_stack.c
index f23b63f0a1c3..b39c60b1f12c 100644
--- a/lib/dump_stack.c
+++ b/lib/dump_stack.c
@@ -33,7 +33,7 @@ asmlinkage void dump_stack(void)
* Permit this cpu to perform nested stack dumps while serialising
* against other CPUs
*/
- preempt_disable();
+ migrate_disable();

retry:
cpu = smp_processor_id();
@@ -52,7 +52,7 @@ retry:
if (!was_locked)
atomic_set(&dump_lock, -1);

- preempt_enable();
+ migrate_enable();
}
#else
asmlinkage void dump_stack(void)
diff --git a/localversion-rt b/localversion-rt
index 2c95a3cdbcb8..e8ada8cdb471 100644
--- a/localversion-rt
+++ b/localversion-rt
@@ -1 +1 @@
--rt72
+-rt73
diff --git a/net/core/dev.c b/net/core/dev.c
index 30fd8898bcfb..cfec8a542d35 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -6231,7 +6231,7 @@ EXPORT_SYMBOL(free_netdev);
void synchronize_net(void)
{
might_sleep();
- if (rtnl_is_locked())
+ if (rtnl_is_locked() && !IS_ENABLED(CONFIG_PREEMPT_RT_FULL))
synchronize_rcu_expedited();
else
synchronize_rcu();
@@ -6481,7 +6481,7 @@ static int dev_cpu_callback(struct notifier_block *nfb,
netif_rx(skb);
input_queue_head_incr(oldsd);
}
- while ((skb = skb_dequeue(&oldsd->input_pkt_queue))) {
+ while ((skb = __skb_dequeue(&oldsd->input_pkt_queue))) {
netif_rx(skb);
input_queue_head_incr(oldsd);
}