Dear RT folks!
I'm pleased to announce the v4.9.11-rt9 patch set.
Changes since v4.9.11-rt8:
- rt_mutex_destroy() is EXPORT_SYMBOL_GPL again. As pointed by Peter
Zijlstra, the removal of _GPL is not required.
- Added a rescheduling point so we don't forget to run a runnable task
at elevated priority under certain circumstances.
- The static initializes for PER_CPU locks were wrong. This affects
the local_locks and resulted in lockdep disabling itself a few
minutes after boot on _big_ iron (100 CPUs+). Reported by Mike
Galbraith and patched by Thomas Gleixner.
Known issues
- CPU hotplug got a little better but can deadlock.
The delta patch against v4.9.11-rt9 is appended below and can be found here:
https://cdn.kernel.org/pub/linux/kernel/projects/rt/4.9/incr/patch-4.9.11-rt8-rt9.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
v4.9.11-rt9
The RT patch against v4.9.11 can be found here:
https://cdn.kernel.org/pub/linux/kernel/projects/rt/4.9/older/patch-4.9.11-rt9.patch.xz
The split quilt queue is available at:
https://cdn.kernel.org/pub/linux/kernel/projects/rt/4.9/older/patches-4.9.11-rt9.tar.xz
Sebastian
diff --git a/include/linux/module.h b/include/linux/module.h
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -496,6 +496,7 @@ static inline int module_is_live(struct module *mod)
struct module *__module_text_address(unsigned long addr);
struct module *__module_address(unsigned long addr);
bool is_module_address(unsigned long addr);
+bool __is_module_percpu_address(unsigned long addr, unsigned long *can_addr);
bool is_module_percpu_address(unsigned long addr);
bool is_module_text_address(unsigned long addr);
diff --git a/include/linux/percpu.h b/include/linux/percpu.h
--- a/include/linux/percpu.h
+++ b/include/linux/percpu.h
@@ -139,6 +139,7 @@ extern int __init pcpu_page_first_chunk(size_t
reserved_size,
#endif
extern void __percpu *__alloc_reserved_percpu(size_t size, size_t align);
+extern bool __is_kernel_percpu_address(unsigned long addr, unsigned long
*can_addr);
extern bool is_kernel_percpu_address(unsigned long addr);
#if !defined(CONFIG_SMP) || !defined(CONFIG_HAVE_SETUP_PER_CPU_AREA)
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -658,6 +658,7 @@ look_up_lock_class(struct lockdep_map *lock, unsigned int
subclass)
struct lockdep_subclass_key *key;
struct hlist_head *hash_head;
struct lock_class *class;
+ bool is_static = false;
if (unlikely(subclass >= MAX_LOCKDEP_SUBCLASSES)) {
debug_locks_off();
@@ -671,10 +672,23 @@ look_up_lock_class(struct lockdep_map *lock, unsigned int
subclass)
/*
* Static locks do not have their class-keys yet - for them the key
- * is the lock object itself:
+ * is the lock object itself. If the lock is in the per cpu area,
+ * the canonical address of the lock (per cpu offset removed) is
+ * used.
*/
- if (unlikely(!lock->key))
- lock->key = (void *)lock;
+ if (unlikely(!lock->key)) {
+ unsigned long can_addr, addr = (unsigned long)lock;
+
+ if (__is_kernel_percpu_address(addr, &can_addr))
+ lock->key = (void *)can_addr;
+ else if (__is_module_percpu_address(addr, &can_addr))
+ lock->key = (void *)can_addr;
+ else if (static_obj(lock))
+ lock->key = (void *)lock;
+ else
+ return ERR_PTR(-EINVAL);
+ is_static = true;
+ }
/*
* NOTE: the class-key must be unique. For dynamic locks, a static
@@ -706,7 +720,7 @@ look_up_lock_class(struct lockdep_map *lock, unsigned int
subclass)
}
}
- return NULL;
+ return is_static || static_obj(lock->key) ? NULL : ERR_PTR(-EINVAL);
}
/*
@@ -724,19 +738,18 @@ register_lock_class(struct lockdep_map *lock, unsigned
int subclass, int force)
DEBUG_LOCKS_WARN_ON(!irqs_disabled());
class = look_up_lock_class(lock, subclass);
- if (likely(class))
+ if (likely(!IS_ERR_OR_NULL(class)))
goto out_set_class_cache;
/*
* Debug-check: all keys must be persistent!
- */
- if (!static_obj(lock->key)) {
+ */
+ if (IS_ERR(class)) {
debug_locks_off();
printk("INFO: trying to register non-static key.\n");
printk("the code is fine but needs lockdep annotation.\n");
printk("turning off the locking correctness validator.\n");
dump_stack();
-
return NULL;
}
@@ -3410,7 +3423,7 @@ static int match_held_lock(struct held_lock *hlock,
struct lockdep_map *lock)
* Clearly if the lock hasn't been acquired _ever_, we're not
* holding it either, so report failure.
*/
- if (!class)
+ if (IS_ERR_OR_NULL(class))
return 0;
/*
@@ -4161,7 +4174,7 @@ void lockdep_reset_lock(struct lockdep_map *lock)
* If the class exists we look it up and zap it:
*/
class = look_up_lock_class(lock, j);
- if (class)
+ if (!IS_ERR_OR_NULL(class))
zap_class(class);
}
/*
diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c
--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -2211,7 +2211,8 @@ void rt_mutex_destroy(struct rt_mutex *lock)
lock->magic = NULL;
#endif
}
-EXPORT_SYMBOL(rt_mutex_destroy);
+
+EXPORT_SYMBOL_GPL(rt_mutex_destroy);
/**
* __rt_mutex_init - initialize the rt lock
diff --git a/kernel/module.c b/kernel/module.c
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -660,16 +660,7 @@ static void percpu_modcopy(struct module *mod,
memcpy(per_cpu_ptr(mod->percpu, cpu), from, size);
}
-/**
- * is_module_percpu_address - test whether address is from module static percpu
- * @addr: address to test
- *
- * Test whether @addr belongs to module static percpu area.
- *
- * RETURNS:
- * %true if @addr is from module static percpu area
- */
-bool is_module_percpu_address(unsigned long addr)
+bool __is_module_percpu_address(unsigned long addr, unsigned long *can_addr)
{
struct module *mod;
unsigned int cpu;
@@ -683,9 +674,11 @@ bool is_module_percpu_address(unsigned long addr)
continue;
for_each_possible_cpu(cpu) {
void *start = per_cpu_ptr(mod->percpu, cpu);
+ void *va = (void *)addr;
- if ((void *)addr >= start &&
- (void *)addr < start + mod->percpu_size) {
+ if (va >= start && va < start + mod->percpu_size) {
+ if (can_addr)
+ *can_addr = (unsigned long) (va -
start);
preempt_enable();
return true;
}
@@ -696,6 +689,20 @@ bool is_module_percpu_address(unsigned long addr)
return false;
}
+/**
+ * is_module_percpu_address - test whether address is from module static percpu
+ * @addr: address to test
+ *
+ * Test whether @addr belongs to module static percpu area.
+ *
+ * RETURNS:
+ * %true if @addr is from module static percpu area
+ */
+bool is_module_percpu_address(unsigned long addr)
+{
+ return __is_module_percpu_address(addr, NULL);
+}
+
#else /* ... !CONFIG_SMP */
static inline void __percpu *mod_percpu(struct module *mod)
diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -1730,12 +1730,11 @@ static void switched_to_dl(struct rq *rq, struct
task_struct *p)
#ifdef CONFIG_SMP
if (tsk_nr_cpus_allowed(p) > 1 && rq->dl.overloaded)
queue_push_tasks(rq);
-#else
+#endif
if (dl_task(rq->curr))
check_preempt_curr_dl(rq, p, 0);
else
resched_curr(rq);
-#endif
}
}
diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
--- a/kernel/sched/rt.c
+++ b/kernel/sched/rt.c
@@ -2200,10 +2200,9 @@ static void switched_to_rt(struct rq *rq, struct
task_struct *p)
#ifdef CONFIG_SMP
if (tsk_nr_cpus_allowed(p) > 1 && rq->rt.overloaded)
queue_push_tasks(rq);
-#else
+#endif /* CONFIG_SMP */
if (p->prio < rq->curr->prio)
resched_curr(rq);
-#endif /* CONFIG_SMP */
}
}
diff --git a/localversion-rt b/localversion-rt
--- a/localversion-rt
+++ b/localversion-rt
@@ -1 +1 @@
--rt8
+-rt9
diff --git a/mm/percpu.c b/mm/percpu.c
--- a/mm/percpu.c
+++ b/mm/percpu.c
@@ -1280,6 +1280,28 @@ void free_percpu(void __percpu *ptr)
}
EXPORT_SYMBOL_GPL(free_percpu);
+bool __is_kernel_percpu_address(unsigned long addr, unsigned long *can_addr)
+{
+#ifdef CONFIG_SMP
+ const size_t static_size = __per_cpu_end - __per_cpu_start;
+ void __percpu *base = __addr_to_pcpu_ptr(pcpu_base_addr);
+ unsigned int cpu;
+
+ for_each_possible_cpu(cpu) {
+ void *start = per_cpu_ptr(base, cpu);
+ void *va = (void *)addr;
+
+ if (va >= start && va < start + static_size) {
+ if (can_addr)
+ *can_addr = (unsigned long) (va - start);
+ return true;
+ }
+ }
+#endif
+ /* on UP, can't distinguish from other static vars, always false */
+ return false;
+}
+
/**
* is_kernel_percpu_address - test whether address is from static percpu area
* @addr: address to test
@@ -1293,20 +1315,7 @@ EXPORT_SYMBOL_GPL(free_percpu);
*/
bool is_kernel_percpu_address(unsigned long addr)
{
-#ifdef CONFIG_SMP
- const size_t static_size = __per_cpu_end - __per_cpu_start;
- void __percpu *base = __addr_to_pcpu_ptr(pcpu_base_addr);
- unsigned int cpu;
-
- for_each_possible_cpu(cpu) {
- void *start = per_cpu_ptr(base, cpu);
-
- if ((void *)addr >= start && (void *)addr < start + static_size)
- return true;
- }
-#endif
- /* on UP, can't distinguish from other static vars, always false */
- return false;
+ return __is_kernel_percpu_address(addr, NULL);
}
/**
