[ANNOUNCE] v4.14.39-rt29

From: Sebastian Andrzej Siewior
Date: Thu May 03 2018 - 12:03:17 EST


Dear RT folks!

I'm pleased to announce the v4.14.39-rt29 patch set.

Changes since v4.14.39-rt28:

- Applied a commit from upstream to avoid a compiler warning. Reported
by Mike Galbraith.

- Annotate sleeping lock context in order to better avoid the RCU
warning if we schedule() within a RCU read section. Another case
reported by Grygorii Strashko.

Known issues
- A warning triggered in "rcu_note_context_switch" originated from
SyS_timer_gettime(). The issue was always there, it is now
visible. Reported by Grygorii Strashko and Daniel Wagner.

The delta patch against v4.14.39-rt28 is appended below and can be found here:

https://cdn.kernel.org/pub/linux/kernel/projects/rt/4.14/incr/patch-4.14.39-rt28-rt29.patch.xz

You can get this release via the git tree at:

git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git v4.14.39-rt29

The RT patch against v4.14.39 can be found here:

https://cdn.kernel.org/pub/linux/kernel/projects/rt/4.14/older/patch-4.14.39-rt29.patch.xz

The split quilt queue is available at:

https://cdn.kernel.org/pub/linux/kernel/projects/rt/4.14/older/patches-4.14.39-rt29.tar.xz

Sebastian

diff --git a/include/linux/sched.h b/include/linux/sched.h
index e305a8f8cd7d..0322503084a5 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -600,6 +600,9 @@ struct task_struct {
int migrate_disable_atomic;
# endif
#endif
+#ifdef CONFIG_PREEMPT_RT_FULL
+ int sleeping_lock;
+#endif

#ifdef CONFIG_PREEMPT_RCU
int rcu_read_lock_nesting;
@@ -1757,6 +1760,23 @@ static __always_inline bool need_resched(void)
return unlikely(tif_need_resched());
}

+#ifdef CONFIG_PREEMPT_RT_FULL
+static inline void sleeping_lock_inc(void)
+{
+ current->sleeping_lock++;
+}
+
+static inline void sleeping_lock_dec(void)
+{
+ current->sleeping_lock--;
+}
+
+#else
+
+static inline void sleeping_lock_inc(void) { }
+static inline void sleeping_lock_dec(void) { }
+#endif
+
/*
* Wrappers for p->thread_info->cpu access. No-op on UP.
*/
diff --git a/include/linux/string.h b/include/linux/string.h
index cfd83eb2f926..96115bf561b4 100644
--- a/include/linux/string.h
+++ b/include/linux/string.h
@@ -28,7 +28,7 @@ extern char * strncpy(char *,const char *, __kernel_size_t);
size_t strlcpy(char *, const char *, size_t);
#endif
#ifndef __HAVE_ARCH_STRSCPY
-ssize_t __must_check strscpy(char *, const char *, size_t);
+ssize_t strscpy(char *, const char *, size_t);
#endif
#ifndef __HAVE_ARCH_STRCAT
extern char * strcat(char *, const char *);
diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c
index 0cb716ba3be0..bac3fb580af6 100644
--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -1141,6 +1141,7 @@ void __sched rt_spin_lock_slowunlock(struct rt_mutex *lock)

void __lockfunc rt_spin_lock(spinlock_t *lock)
{
+ sleeping_lock_inc();
migrate_disable();
spin_acquire(&lock->dep_map, 0, 0, _RET_IP_);
rt_spin_lock_fastlock(&lock->lock, rt_spin_lock_slowlock);
@@ -1155,6 +1156,7 @@ void __lockfunc __rt_spin_lock(struct rt_mutex *lock)
#ifdef CONFIG_DEBUG_LOCK_ALLOC
void __lockfunc rt_spin_lock_nested(spinlock_t *lock, int subclass)
{
+ sleeping_lock_inc();
migrate_disable();
spin_acquire(&lock->dep_map, subclass, 0, _RET_IP_);
rt_spin_lock_fastlock(&lock->lock, rt_spin_lock_slowlock);
@@ -1168,6 +1170,7 @@ void __lockfunc rt_spin_unlock(spinlock_t *lock)
spin_release(&lock->dep_map, 1, _RET_IP_);
rt_spin_lock_fastunlock(&lock->lock, rt_spin_lock_slowunlock);
migrate_enable();
+ sleeping_lock_dec();
}
EXPORT_SYMBOL(rt_spin_unlock);

@@ -1193,12 +1196,15 @@ int __lockfunc rt_spin_trylock(spinlock_t *lock)
{
int ret;

+ sleeping_lock_inc();
migrate_disable();
ret = __rt_mutex_trylock(&lock->lock);
- if (ret)
+ if (ret) {
spin_acquire(&lock->dep_map, 0, 1, _RET_IP_);
- else
+ } else {
migrate_enable();
+ sleeping_lock_dec();
+ }
return ret;
}
EXPORT_SYMBOL(rt_spin_trylock);
@@ -1210,6 +1216,7 @@ int __lockfunc rt_spin_trylock_bh(spinlock_t *lock)
local_bh_disable();
ret = __rt_mutex_trylock(&lock->lock);
if (ret) {
+ sleeping_lock_inc();
migrate_disable();
spin_acquire(&lock->dep_map, 0, 1, _RET_IP_);
} else
@@ -1225,6 +1232,7 @@ int __lockfunc rt_spin_trylock_irqsave(spinlock_t *lock, unsigned long *flags)
*flags = 0;
ret = __rt_mutex_trylock(&lock->lock);
if (ret) {
+ sleeping_lock_inc();
migrate_disable();
spin_acquire(&lock->dep_map, 0, 1, _RET_IP_);
}
diff --git a/kernel/locking/rwlock-rt.c b/kernel/locking/rwlock-rt.c
index aebb7ce25bc6..f2e155b2c4a8 100644
--- a/kernel/locking/rwlock-rt.c
+++ b/kernel/locking/rwlock-rt.c
@@ -305,12 +305,15 @@ int __lockfunc rt_read_trylock(rwlock_t *rwlock)
{
int ret;

+ sleeping_lock_inc();
migrate_disable();
ret = do_read_rt_trylock(rwlock);
- if (ret)
+ if (ret) {
rwlock_acquire_read(&rwlock->dep_map, 0, 1, _RET_IP_);
- else
+ } else {
migrate_enable();
+ sleeping_lock_dec();
+ }
return ret;
}
EXPORT_SYMBOL(rt_read_trylock);
@@ -319,18 +322,22 @@ int __lockfunc rt_write_trylock(rwlock_t *rwlock)
{
int ret;

+ sleeping_lock_inc();
migrate_disable();
ret = do_write_rt_trylock(rwlock);
- if (ret)
+ if (ret) {
rwlock_acquire(&rwlock->dep_map, 0, 1, _RET_IP_);
- else
+ } else {
migrate_enable();
+ sleeping_lock_dec();
+ }
return ret;
}
EXPORT_SYMBOL(rt_write_trylock);

void __lockfunc rt_read_lock(rwlock_t *rwlock)
{
+ sleeping_lock_inc();
migrate_disable();
rwlock_acquire_read(&rwlock->dep_map, 0, 0, _RET_IP_);
do_read_rt_lock(rwlock);
@@ -339,6 +346,7 @@ EXPORT_SYMBOL(rt_read_lock);

void __lockfunc rt_write_lock(rwlock_t *rwlock)
{
+ sleeping_lock_inc();
migrate_disable();
rwlock_acquire(&rwlock->dep_map, 0, 0, _RET_IP_);
do_write_rt_lock(rwlock);
@@ -350,6 +358,7 @@ void __lockfunc rt_read_unlock(rwlock_t *rwlock)
rwlock_release(&rwlock->dep_map, 1, _RET_IP_);
do_read_rt_unlock(rwlock);
migrate_enable();
+ sleeping_lock_dec();
}
EXPORT_SYMBOL(rt_read_unlock);

@@ -358,6 +367,7 @@ void __lockfunc rt_write_unlock(rwlock_t *rwlock)
rwlock_release(&rwlock->dep_map, 1, _RET_IP_);
do_write_rt_unlock(rwlock);
migrate_enable();
+ sleeping_lock_dec();
}
EXPORT_SYMBOL(rt_write_unlock);

diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index 3315ebad932f..c6098f60e641 100644
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -301,13 +301,13 @@ static void rcu_preempt_note_context_switch(bool preempt)
struct task_struct *t = current;
struct rcu_data *rdp;
struct rcu_node *rnp;
- int mg_counter = 0;
+ int sleeping_l = 0;

RCU_LOCKDEP_WARN(!irqs_disabled(), "rcu_preempt_note_context_switch() invoked with interrupts enabled!!!\n");
-#if defined(CONFIG_PREEMPT_RT_BASE)
- mg_counter = t->migrate_disable;
+#if defined(CONFIG_PREEMPT_RT_FULL)
+ sleeping_l = t->sleeping_lock;
#endif
- WARN_ON_ONCE(!preempt && t->rcu_read_lock_nesting > 0 && !mg_counter);
+ WARN_ON_ONCE(!preempt && t->rcu_read_lock_nesting > 0 && !sleeping_l);
if (t->rcu_read_lock_nesting > 0 &&
!t->rcu_read_unlock_special.b.blocked) {

diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c
index ce2c2d04cbaa..b59e009087a9 100644
--- a/kernel/time/hrtimer.c
+++ b/kernel/time/hrtimer.c
@@ -1870,7 +1870,9 @@ void cpu_chill(void)
chill_time = ktime_set(0, NSEC_PER_MSEC);
set_current_state(TASK_UNINTERRUPTIBLE);
current->flags |= PF_NOFREEZE;
+ sleeping_lock_inc();
schedule_hrtimeout(&chill_time, HRTIMER_MODE_REL_HARD);
+ sleeping_lock_dec();
if (!freeze_flag)
current->flags &= ~PF_NOFREEZE;
}
diff --git a/localversion-rt b/localversion-rt
index 5a64c9c2ab61..90290c642ed5 100644
--- a/localversion-rt
+++ b/localversion-rt
@@ -1 +1 @@
--rt28
+-rt29