[ANNOUNCE] 3.14.72-rt76

From: Steven Rostedt
Date: Thu Jul 14 2016 - 10:58:25 EST


Dear RT Folks,

I'm pleased to announce the 3.14.72-rt76 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: v3.14-rt
Head SHA1: e9deb8e0208728e04f658d89e60e641f0beefe54


Or to build 3.14.72-rt76 directly, the following patches should be applied:

http://www.kernel.org/pub/linux/kernel/v3.x/linux-3.14.tar.xz

http://www.kernel.org/pub/linux/kernel/v3.x/patch-3.14.72.xz

http://www.kernel.org/pub/linux/kernel/projects/rt/3.14/patch-3.14.72-rt76.patch.xz



You can also build from 3.14.72-rt75 by applying the incremental patch:

http://www.kernel.org/pub/linux/kernel/projects/rt/3.14/incr/patch-3.14.72-rt75-rt76.patch.xz



Enjoy,

-- Steve


Changes from v3.14.72-rt75:

---

Corey Minyard (1):
x86: Fix an RT MCE crash

Josh Cartwright (1):
list_bl: fixup bogus lockdep warning

Luiz Capitulino (1):
mm: perform lru_add_drain_all() remotely

Mike Galbraith (1):
mm/zsmalloc: Use get/put_cpu_light in zs_map_object()/zs_unmap_object()

Peter Zijlstra (1):
sched,preempt: Fix preempt_count manipulations

Rik van Riel (1):
kvm, rt: change async pagefault code locking for PREEMPT_RT

Sebastian Andrzej Siewior (5):
net: dev: always take qdisc's busylock in __dev_xmit_skb()
kernel/printk: Don't try to print from IRQ/NMI region
arm: lazy preempt: correct resched condition
locallock: add local_lock_on()
trace: correct off by one while recording the trace-event

Steven Rostedt (Red Hat) (1):
Linux 3.14.72-rt76

Thomas Gleixner (1):
perf/x86/intel/rapl: Make PMU lock raw

----
arch/arm/kernel/entry-armv.S | 6 ++++-
arch/x86/kernel/cpu/mcheck/mce.c | 3 ++-
arch/x86/kernel/cpu/perf_event_intel_rapl.c | 20 ++++++++--------
arch/x86/kernel/kvm.c | 37 +++++++++++++++--------------
include/asm-generic/preempt.h | 4 ++--
include/linux/list_bl.h | 12 ++++++----
include/linux/locallock.h | 6 +++++
include/trace/ftrace.h | 3 +++
kernel/printk/printk.c | 10 ++++++++
localversion-rt | 2 +-
mm/swap.c | 37 +++++++++++++++++++++++------
mm/zsmalloc.c | 4 ++--
net/core/dev.c | 4 ++++
13 files changed, 101 insertions(+), 47 deletions(-)
---------------------------
diff --git a/arch/arm/kernel/entry-armv.S b/arch/arm/kernel/entry-armv.S
index 62bc04cc9b7d..ceda9997a29d 100644
--- a/arch/arm/kernel/entry-armv.S
+++ b/arch/arm/kernel/entry-armv.S
@@ -234,7 +234,11 @@ svc_preempt:
bne 1b
tst r0, #_TIF_NEED_RESCHED_LAZY
moveq pc, r8 @ go again
- b 1b
+ ldr r0, [tsk, #TI_PREEMPT_LAZY] @ get preempt lazy count
+ teq r0, #0 @ if preempt lazy count != 0
+ beq 1b
+ mov pc, r8 @ go again
+
#endif

__und_fault:
diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c
index d4867bd532f3..31ec14000e4a 100644
--- a/arch/x86/kernel/cpu/mcheck/mce.c
+++ b/arch/x86/kernel/cpu/mcheck/mce.c
@@ -1403,7 +1403,8 @@ static int mce_notify_work_init(void)

static void mce_notify_work(void)
{
- wake_up_process(mce_notify_helper);
+ if (mce_notify_helper)
+ wake_up_process(mce_notify_helper);
}
#else
static void mce_notify_work(void)
diff --git a/arch/x86/kernel/cpu/perf_event_intel_rapl.c b/arch/x86/kernel/cpu/perf_event_intel_rapl.c
index 95700e52061d..4d270d910c33 100644
--- a/arch/x86/kernel/cpu/perf_event_intel_rapl.c
+++ b/arch/x86/kernel/cpu/perf_event_intel_rapl.c
@@ -98,7 +98,7 @@ static struct kobj_attribute format_attr_##_var = \
#define RAPL_CNTR_WIDTH 32 /* 32-bit rapl counters */

struct rapl_pmu {
- spinlock_t lock;
+ raw_spinlock_t lock;
int hw_unit; /* 1/2^hw_unit Joule */
int n_active; /* number of active events */
struct list_head active_list;
@@ -188,13 +188,13 @@ static enum hrtimer_restart rapl_hrtimer_handle(struct hrtimer *hrtimer)
if (!pmu->n_active)
return HRTIMER_NORESTART;

- spin_lock_irqsave(&pmu->lock, flags);
+ raw_spin_lock_irqsave(&pmu->lock, flags);

list_for_each_entry(event, &pmu->active_list, active_entry) {
rapl_event_update(event);
}

- spin_unlock_irqrestore(&pmu->lock, flags);
+ raw_spin_unlock_irqrestore(&pmu->lock, flags);

hrtimer_forward_now(hrtimer, pmu->timer_interval);

@@ -231,9 +231,9 @@ static void rapl_pmu_event_start(struct perf_event *event, int mode)
struct rapl_pmu *pmu = __get_cpu_var(rapl_pmu);
unsigned long flags;

- spin_lock_irqsave(&pmu->lock, flags);
+ raw_spin_lock_irqsave(&pmu->lock, flags);
__rapl_pmu_event_start(pmu, event);
- spin_unlock_irqrestore(&pmu->lock, flags);
+ raw_spin_unlock_irqrestore(&pmu->lock, flags);
}

static void rapl_pmu_event_stop(struct perf_event *event, int mode)
@@ -242,7 +242,7 @@ static void rapl_pmu_event_stop(struct perf_event *event, int mode)
struct hw_perf_event *hwc = &event->hw;
unsigned long flags;

- spin_lock_irqsave(&pmu->lock, flags);
+ raw_spin_lock_irqsave(&pmu->lock, flags);

/* mark event as deactivated and stopped */
if (!(hwc->state & PERF_HES_STOPPED)) {
@@ -267,7 +267,7 @@ static void rapl_pmu_event_stop(struct perf_event *event, int mode)
hwc->state |= PERF_HES_UPTODATE;
}

- spin_unlock_irqrestore(&pmu->lock, flags);
+ raw_spin_unlock_irqrestore(&pmu->lock, flags);
}

static int rapl_pmu_event_add(struct perf_event *event, int mode)
@@ -276,14 +276,14 @@ static int rapl_pmu_event_add(struct perf_event *event, int mode)
struct hw_perf_event *hwc = &event->hw;
unsigned long flags;

- spin_lock_irqsave(&pmu->lock, flags);
+ raw_spin_lock_irqsave(&pmu->lock, flags);

hwc->state = PERF_HES_UPTODATE | PERF_HES_STOPPED;

if (mode & PERF_EF_START)
__rapl_pmu_event_start(pmu, event);

- spin_unlock_irqrestore(&pmu->lock, flags);
+ raw_spin_unlock_irqrestore(&pmu->lock, flags);

return 0;
}
@@ -526,7 +526,7 @@ static int rapl_cpu_prepare(int cpu)
if (!pmu)
return -1;

- spin_lock_init(&pmu->lock);
+ raw_spin_lock_init(&pmu->lock);

INIT_LIST_HEAD(&pmu->active_list);

diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index 0b1e1d5dbc5b..7606d7c35bd2 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -35,6 +35,7 @@
#include <linux/slab.h>
#include <linux/kprobes.h>
#include <linux/debugfs.h>
+#include <linux/wait-simple.h>
#include <asm/timer.h>
#include <asm/cpu.h>
#include <asm/traps.h>
@@ -90,14 +91,14 @@ static void kvm_io_delay(void)

struct kvm_task_sleep_node {
struct hlist_node link;
- wait_queue_head_t wq;
+ struct swait_head wq;
u32 token;
int cpu;
bool halted;
};

static struct kvm_task_sleep_head {
- spinlock_t lock;
+ raw_spinlock_t lock;
struct hlist_head list;
} async_pf_sleepers[KVM_TASK_SLEEP_HASHSIZE];

@@ -121,17 +122,17 @@ void kvm_async_pf_task_wait(u32 token)
u32 key = hash_32(token, KVM_TASK_SLEEP_HASHBITS);
struct kvm_task_sleep_head *b = &async_pf_sleepers[key];
struct kvm_task_sleep_node n, *e;
- DEFINE_WAIT(wait);
+ DEFINE_SWAITER(wait);

rcu_irq_enter();

- spin_lock(&b->lock);
+ raw_spin_lock(&b->lock);
e = _find_apf_task(b, token);
if (e) {
/* dummy entry exist -> wake up was delivered ahead of PF */
hlist_del(&e->link);
kfree(e);
- spin_unlock(&b->lock);
+ raw_spin_unlock(&b->lock);

rcu_irq_exit();
return;
@@ -140,13 +141,13 @@ void kvm_async_pf_task_wait(u32 token)
n.token = token;
n.cpu = smp_processor_id();
n.halted = is_idle_task(current) || preempt_count() > 1;
- init_waitqueue_head(&n.wq);
+ init_swait_head(&n.wq);
hlist_add_head(&n.link, &b->list);
- spin_unlock(&b->lock);
+ raw_spin_unlock(&b->lock);

for (;;) {
if (!n.halted)
- prepare_to_wait(&n.wq, &wait, TASK_UNINTERRUPTIBLE);
+ swait_prepare(&n.wq, &wait, TASK_UNINTERRUPTIBLE);
if (hlist_unhashed(&n.link))
break;

@@ -165,7 +166,7 @@ void kvm_async_pf_task_wait(u32 token)
}
}
if (!n.halted)
- finish_wait(&n.wq, &wait);
+ swait_finish(&n.wq, &wait);

rcu_irq_exit();
return;
@@ -177,8 +178,8 @@ static void apf_task_wake_one(struct kvm_task_sleep_node *n)
hlist_del_init(&n->link);
if (n->halted)
smp_send_reschedule(n->cpu);
- else if (waitqueue_active(&n->wq))
- wake_up(&n->wq);
+ else if (swaitqueue_active(&n->wq))
+ swait_wake(&n->wq);
}

static void apf_task_wake_all(void)
@@ -188,14 +189,14 @@ static void apf_task_wake_all(void)
for (i = 0; i < KVM_TASK_SLEEP_HASHSIZE; i++) {
struct hlist_node *p, *next;
struct kvm_task_sleep_head *b = &async_pf_sleepers[i];
- spin_lock(&b->lock);
+ raw_spin_lock(&b->lock);
hlist_for_each_safe(p, next, &b->list) {
struct kvm_task_sleep_node *n =
hlist_entry(p, typeof(*n), link);
if (n->cpu == smp_processor_id())
apf_task_wake_one(n);
}
- spin_unlock(&b->lock);
+ raw_spin_unlock(&b->lock);
}
}

@@ -211,7 +212,7 @@ void kvm_async_pf_task_wake(u32 token)
}

again:
- spin_lock(&b->lock);
+ raw_spin_lock(&b->lock);
n = _find_apf_task(b, token);
if (!n) {
/*
@@ -224,17 +225,17 @@ again:
* Allocation failed! Busy wait while other cpu
* handles async PF.
*/
- spin_unlock(&b->lock);
+ raw_spin_unlock(&b->lock);
cpu_relax();
goto again;
}
n->token = token;
n->cpu = smp_processor_id();
- init_waitqueue_head(&n->wq);
+ init_swait_head(&n->wq);
hlist_add_head(&n->link, &b->list);
} else
apf_task_wake_one(n);
- spin_unlock(&b->lock);
+ raw_spin_unlock(&b->lock);
return;
}
EXPORT_SYMBOL_GPL(kvm_async_pf_task_wake);
@@ -484,7 +485,7 @@ void __init kvm_guest_init(void)
paravirt_ops_setup();
register_reboot_notifier(&kvm_pv_reboot_nb);
for (i = 0; i < KVM_TASK_SLEEP_HASHSIZE; i++)
- spin_lock_init(&async_pf_sleepers[i].lock);
+ raw_spin_lock_init(&async_pf_sleepers[i].lock);
if (kvm_para_has_feature(KVM_FEATURE_ASYNC_PF))
x86_init.irqs.trap_init = kvm_apf_trap_init;

diff --git a/include/asm-generic/preempt.h b/include/asm-generic/preempt.h
index 54352f4dde1a..65759d8b0b46 100644
--- a/include/asm-generic/preempt.h
+++ b/include/asm-generic/preempt.h
@@ -7,10 +7,10 @@

static __always_inline int preempt_count(void)
{
- return current_thread_info()->preempt_count;
+ return READ_ONCE(current_thread_info()->preempt_count);
}

-static __always_inline int *preempt_count_ptr(void)
+static __always_inline volatile int *preempt_count_ptr(void)
{
return &current_thread_info()->preempt_count;
}
diff --git a/include/linux/list_bl.h b/include/linux/list_bl.h
index d8876a0cf036..017d0f1c1eb4 100644
--- a/include/linux/list_bl.h
+++ b/include/linux/list_bl.h
@@ -42,13 +42,15 @@ struct hlist_bl_node {
struct hlist_bl_node *next, **pprev;
};

-static inline void INIT_HLIST_BL_HEAD(struct hlist_bl_head *h)
-{
- h->first = NULL;
#ifdef CONFIG_PREEMPT_RT_BASE
- raw_spin_lock_init(&h->lock);
+#define INIT_HLIST_BL_HEAD(h) \
+do { \
+ (h)->first = NULL; \
+ raw_spin_lock_init(&(h)->lock); \
+} while (0)
+#else
+#define INIT_HLIST_BL_HEAD(h) (h)->first = NULL
#endif
-}

static inline void INIT_HLIST_BL_NODE(struct hlist_bl_node *h)
{
diff --git a/include/linux/locallock.h b/include/linux/locallock.h
index 21653e9bfa20..015271ff8ec8 100644
--- a/include/linux/locallock.h
+++ b/include/linux/locallock.h
@@ -66,6 +66,9 @@ static inline void __local_lock(struct local_irq_lock *lv)
#define local_lock(lvar) \
do { __local_lock(&get_local_var(lvar)); } while (0)

+#define local_lock_on(lvar, cpu) \
+ do { __local_lock(&per_cpu(lvar, cpu)); } while (0)
+
static inline int __local_trylock(struct local_irq_lock *lv)
{
if (lv->owner != current && spin_trylock_local(&lv->lock)) {
@@ -104,6 +107,9 @@ static inline void __local_unlock(struct local_irq_lock *lv)
put_local_var(lvar); \
} while (0)

+#define local_unlock_on(lvar, cpu) \
+ do { __local_unlock(&per_cpu(lvar, cpu)); } while (0)
+
static inline void __local_lock_irq(struct local_irq_lock *lv)
{
spin_lock_irqsave(&lv->lock, lv->flags);
diff --git a/include/trace/ftrace.h b/include/trace/ftrace.h
index 1ee19a24cc5f..73a9f766e904 100644
--- a/include/trace/ftrace.h
+++ b/include/trace/ftrace.h
@@ -555,6 +555,9 @@ ftrace_raw_event_##call(void *__data, proto) \
\
local_save_flags(irq_flags); \
pc = preempt_count(); \
+ /* Account for tracepoint preempt disable */ \
+ if (IS_ENABLED(CONFIG_PREEMPT)) \
+ pc--; \
\
__data_size = ftrace_get_offsets_##call(&__data_offsets, args); \
\
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index 0b47939efd62..4472339e2156 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -1289,6 +1289,11 @@ static void call_console_drivers(int level, const char *text, size_t len)
if (!console_drivers)
return;

+ if (IS_ENABLED(CONFIG_PREEMPT_RT_BASE)) {
+ if (in_irq() || in_nmi())
+ return;
+ }
+
migrate_disable();
for_each_console(con) {
if (exclusive_console && con != exclusive_console)
@@ -2214,6 +2219,11 @@ void console_unblank(void)
{
struct console *c;

+ if (IS_ENABLED(CONFIG_PREEMPT_RT_BASE)) {
+ if (in_irq() || in_nmi())
+ return;
+ }
+
/*
* console_unblank can no longer be called in interrupt context unless
* oops_in_progress is set to 1..
diff --git a/localversion-rt b/localversion-rt
index 54e7da6f49fb..c1f2720eaf25 100644
--- a/localversion-rt
+++ b/localversion-rt
@@ -1 +1 @@
--rt75
+-rt76
diff --git a/mm/swap.c b/mm/swap.c
index 9a9d4c7da2cc..a9064ed57fc2 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -750,9 +750,15 @@ void lru_add_drain_cpu(int cpu)
unsigned long flags;

/* No harm done if a racing interrupt already did this */
+#ifdef CONFIG_PREEMPT_RT_BASE
+ local_lock_irqsave_on(rotate_lock, flags, cpu);
+ pagevec_move_tail(pvec);
+ local_unlock_irqrestore_on(rotate_lock, flags, cpu);
+#else
local_lock_irqsave(rotate_lock, flags);
pagevec_move_tail(pvec);
local_unlock_irqrestore(rotate_lock, flags);
+#endif
}

pvec = &per_cpu(lru_deactivate_pvecs, cpu);
@@ -795,12 +801,32 @@ void lru_add_drain(void)
local_unlock_cpu(swapvec_lock);
}

+
+#ifdef CONFIG_PREEMPT_RT_BASE
+static inline void remote_lru_add_drain(int cpu, struct cpumask *has_work)
+{
+ local_lock_on(swapvec_lock, cpu);
+ lru_add_drain_cpu(cpu);
+ local_unlock_on(swapvec_lock, cpu);
+}
+
+#else
+
static void lru_add_drain_per_cpu(struct work_struct *dummy)
{
lru_add_drain();
}

static DEFINE_PER_CPU(struct work_struct, lru_add_drain_work);
+static inline void remote_lru_add_drain(int cpu, struct cpumask *has_work)
+{
+ struct work_struct *work = &per_cpu(lru_add_drain_work, cpu);
+
+ INIT_WORK(work, lru_add_drain_per_cpu);
+ schedule_work_on(cpu, work);
+ cpumask_set_cpu(cpu, has_work);
+}
+#endif

void lru_add_drain_all(void)
{
@@ -813,20 +839,17 @@ void lru_add_drain_all(void)
cpumask_clear(&has_work);

for_each_online_cpu(cpu) {
- struct work_struct *work = &per_cpu(lru_add_drain_work, cpu);
-
if (pagevec_count(&per_cpu(lru_add_pvec, cpu)) ||
pagevec_count(&per_cpu(lru_rotate_pvecs, cpu)) ||
pagevec_count(&per_cpu(lru_deactivate_pvecs, cpu)) ||
- need_activate_page_drain(cpu)) {
- INIT_WORK(work, lru_add_drain_per_cpu);
- schedule_work_on(cpu, work);
- cpumask_set_cpu(cpu, &has_work);
- }
+ need_activate_page_drain(cpu))
+ remote_lru_add_drain(cpu, &has_work);
}

+#ifndef CONFIG_PREEMPT_RT_BASE
for_each_cpu(cpu, &has_work)
flush_work(&per_cpu(lru_add_drain_work, cpu));
+#endif

put_online_cpus();
mutex_unlock(&lock);
diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
index c03ca5e9fe15..df9c7a189118 100644
--- a/mm/zsmalloc.c
+++ b/mm/zsmalloc.c
@@ -1037,7 +1037,7 @@ void *zs_map_object(struct zs_pool *pool, unsigned long handle,
class = &pool->size_class[class_idx];
off = obj_idx_to_offset(page, obj_idx, class->size);

- area = &get_cpu_var(zs_map_area);
+ area = per_cpu_ptr(&zs_map_area, get_cpu_light());
area->vm_mm = mm;
if (off + class->size <= PAGE_SIZE) {
/* this object is contained entirely within a page */
@@ -1083,7 +1083,7 @@ void zs_unmap_object(struct zs_pool *pool, unsigned long handle)

__zs_unmap_object(area, pages, off, class->size);
}
- put_cpu_var(zs_map_area);
+ put_cpu_light();
}
EXPORT_SYMBOL_GPL(zs_unmap_object);

diff --git a/net/core/dev.c b/net/core/dev.c
index 4259edb6d29b..0a680b4adf35 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -2720,7 +2720,11 @@ static inline int __dev_xmit_skb(struct sk_buff *skb, struct Qdisc *q,
* This permits __QDISC_STATE_RUNNING owner to get the lock more often
* and dequeue packets faster.
*/
+#ifdef CONFIG_PREEMPT_RT_FULL
+ contended = true;
+#else
contended = qdisc_is_running(q);
+#endif
if (unlikely(contended))
spin_lock(&q->busylock);