[PATCH] lockdep: prove spinlock rwlock locking correctness

Use the lock validator framework to prove spinlock and rwlock locking
correctness.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

3 files changed, 81 insertions, 9 deletions

diff --git a/kernel/Makefile b/kernel/Makefile
index df6ef3263699..47dbcd570cd8 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -27,6 +27,7 @@ obj-$(CONFIG_RT_MUTEX_TESTER) += rtmutex-tester.o
 obj-$(CONFIG_GENERIC_ISA_DMA) += dma.o
 obj-$(CONFIG_SMP) += cpu.o spinlock.o
 obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock.o
+obj-$(CONFIG_PROVE_LOCKING) += spinlock.o
 obj-$(CONFIG_UID16) += uid16.o
 obj-$(CONFIG_MODULES) += module.o
 obj-$(CONFIG_KALLSYMS) += kallsyms.o
diff --git a/kernel/sched.c b/kernel/sched.c
index 911829966534..ae4db0185bb2 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -308,6 +308,13 @@ static inline void finish_lock_switch(runqueue_t *rq, task_t *prev)
 	/* this is a valid case when another task releases the spinlock */
 	rq->lock.owner = current;
 #endif
+	/*
+	 * If we are tracking spinlock dependencies then we have to
+	 * fix up the runqueue lock - which gets 'carried over' from
+	 * prev into current:
+	 */
+	spin_acquire(&rq->lock.dep_map, 0, 0, _THIS_IP_);
+
 	spin_unlock_irq(&rq->lock);
 }
 
@@ -1778,6 +1785,7 @@ task_t * context_switch(runqueue_t *rq, task_t *prev, task_t *next)
 		WARN_ON(rq->prev_mm);
 		rq->prev_mm = oldmm;
 	}
+	spin_release(&rq->lock.dep_map, 1, _THIS_IP_);
 
 	/* Here we just switch the register state and the stack. */
 	switch_to(prev, next, prev);
@@ -4384,6 +4392,7 @@ asmlinkage long sys_sched_yield(void)
 	 * no need to preempt or enable interrupts:
 	 */
 	__release(rq->lock);
+	spin_release(&rq->lock.dep_map, 1, _THIS_IP_);
 	_raw_spin_unlock(&rq->lock);
 	preempt_enable_no_resched();
 
@@ -4447,6 +4456,7 @@ int cond_resched_lock(spinlock_t *lock)
 		spin_lock(lock);
 	}
 	if (need_resched() && __resched_legal()) {
+		spin_release(&lock->dep_map, 1, _THIS_IP_);
 		_raw_spin_unlock(lock);
 		preempt_enable_no_resched();
 		__cond_resched();
diff --git a/kernel/spinlock.c b/kernel/spinlock.c
index b31e54eadf56..bfd6ad9c0330 100644
--- a/kernel/spinlock.c
+++ b/kernel/spinlock.c
@@ -13,6 +13,7 @@
 #include <linux/preempt.h>
 #include <linux/spinlock.h>
 #include <linux/interrupt.h>
+#include <linux/debug_locks.h>
 #include <linux/module.h>
 
 /*
@@ -29,8 +30,10 @@ EXPORT_SYMBOL(generic__raw_read_trylock);
 int __lockfunc _spin_trylock(spinlock_t *lock)
 {
 	preempt_disable();
-	if (_raw_spin_trylock(lock))
+	if (_raw_spin_trylock(lock)) {
+		spin_acquire(&lock->dep_map, 0, 1, _RET_IP_);
 		return 1;
+	}
 	
 	preempt_enable();
 	return 0;
@@ -40,8 +43,10 @@ EXPORT_SYMBOL(_spin_trylock);
 int __lockfunc _read_trylock(rwlock_t *lock)
 {
 	preempt_disable();
-	if (_raw_read_trylock(lock))
+	if (_raw_read_trylock(lock)) {
+		rwlock_acquire_read(&lock->dep_map, 0, 1, _RET_IP_);
 		return 1;
+	}
 
 	preempt_enable();
 	return 0;
@@ -51,19 +56,28 @@ EXPORT_SYMBOL(_read_trylock);
 int __lockfunc _write_trylock(rwlock_t *lock)
 {
 	preempt_disable();
-	if (_raw_write_trylock(lock))
+	if (_raw_write_trylock(lock)) {
+		rwlock_acquire(&lock->dep_map, 0, 1, _RET_IP_);
 		return 1;
+	}
 
 	preempt_enable();
 	return 0;
 }
 EXPORT_SYMBOL(_write_trylock);
 
-#if !defined(CONFIG_PREEMPT) || !defined(CONFIG_SMP)
+/*
+ * If lockdep is enabled then we use the non-preemption spin-ops
+ * even on CONFIG_PREEMPT, because lockdep assumes that interrupts are
+ * not re-enabled during lock-acquire (which the preempt-spin-ops do):
+ */
+#if !defined(CONFIG_PREEMPT) || !defined(CONFIG_SMP) || \
+	defined(CONFIG_PROVE_LOCKING)
 
 void __lockfunc _read_lock(rwlock_t *lock)
 {
 	preempt_disable();
+	rwlock_acquire_read(&lock->dep_map, 0, 0, _RET_IP_);
 	_raw_read_lock(lock);
 }
 EXPORT_SYMBOL(_read_lock);
@@ -74,7 +88,17 @@ unsigned long __lockfunc _spin_lock_irqsave(spinlock_t *lock)
 
 	local_irq_save(flags);
 	preempt_disable();
+	spin_acquire(&lock->dep_map, 0, 0, _RET_IP_);
+	/*
+	 * On lockdep we dont want the hand-coded irq-enable of
+	 * _raw_spin_lock_flags() code, because lockdep assumes
+	 * that interrupts are not re-enabled during lock-acquire:
+	 */
+#ifdef CONFIG_PROVE_LOCKING
+	_raw_spin_lock(lock);
+#else
 	_raw_spin_lock_flags(lock, &flags);
+#endif
 	return flags;
 }
 EXPORT_SYMBOL(_spin_lock_irqsave);
@@ -83,6 +107,7 @@ void __lockfunc _spin_lock_irq(spinlock_t *lock)
 {
 	local_irq_disable();
 	preempt_disable();
+	spin_acquire(&lock->dep_map, 0, 0, _RET_IP_);
 	_raw_spin_lock(lock);
 }
 EXPORT_SYMBOL(_spin_lock_irq);
@@ -91,6 +116,7 @@ void __lockfunc _spin_lock_bh(spinlock_t *lock)
 {
 	local_bh_disable();
 	preempt_disable();
+	spin_acquire(&lock->dep_map, 0, 0, _RET_IP_);
 	_raw_spin_lock(lock);
 }
 EXPORT_SYMBOL(_spin_lock_bh);
@@ -101,6 +127,7 @@ unsigned long __lockfunc _read_lock_irqsave(rwlock_t *lock)
 
 	local_irq_save(flags);
 	preempt_disable();
+	rwlock_acquire_read(&lock->dep_map, 0, 0, _RET_IP_);
 	_raw_read_lock(lock);
 	return flags;
 }
@@ -110,6 +137,7 @@ void __lockfunc _read_lock_irq(rwlock_t *lock)
 {
 	local_irq_disable();
 	preempt_disable();
+	rwlock_acquire_read(&lock->dep_map, 0, 0, _RET_IP_);
 	_raw_read_lock(lock);
 }
 EXPORT_SYMBOL(_read_lock_irq);
@@ -118,6 +146,7 @@ void __lockfunc _read_lock_bh(rwlock_t *lock)
 {
 	local_bh_disable();
 	preempt_disable();
+	rwlock_acquire_read(&lock->dep_map, 0, 0, _RET_IP_);
 	_raw_read_lock(lock);
 }
 EXPORT_SYMBOL(_read_lock_bh);
@@ -128,6 +157,7 @@ unsigned long __lockfunc _write_lock_irqsave(rwlock_t *lock)
 
 	local_irq_save(flags);
 	preempt_disable();
+	rwlock_acquire(&lock->dep_map, 0, 0, _RET_IP_);
 	_raw_write_lock(lock);
 	return flags;
 }
@@ -137,6 +167,7 @@ void __lockfunc _write_lock_irq(rwlock_t *lock)
 {
 	local_irq_disable();
 	preempt_disable();
+	rwlock_acquire(&lock->dep_map, 0, 0, _RET_IP_);
 	_raw_write_lock(lock);
 }
 EXPORT_SYMBOL(_write_lock_irq);
@@ -145,6 +176,7 @@ void __lockfunc _write_lock_bh(rwlock_t *lock)
 {
 	local_bh_disable();
 	preempt_disable();
+	rwlock_acquire(&lock->dep_map, 0, 0, _RET_IP_);
 	_raw_write_lock(lock);
 }
 EXPORT_SYMBOL(_write_lock_bh);
@@ -152,6 +184,7 @@ EXPORT_SYMBOL(_write_lock_bh);
 void __lockfunc _spin_lock(spinlock_t *lock)
 {
 	preempt_disable();
+	spin_acquire(&lock->dep_map, 0, 0, _RET_IP_);
 	_raw_spin_lock(lock);
 }
 
@@ -160,6 +193,7 @@ EXPORT_SYMBOL(_spin_lock);
 void __lockfunc _write_lock(rwlock_t *lock)
 {
 	preempt_disable();
+	rwlock_acquire(&lock->dep_map, 0, 0, _RET_IP_);
 	_raw_write_lock(lock);
 }
 
@@ -255,8 +289,22 @@ BUILD_LOCK_OPS(write, rwlock);
 
 #endif /* CONFIG_PREEMPT */
 
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+
+void __lockfunc _spin_lock_nested(spinlock_t *lock, int subclass)
+{
+	preempt_disable();
+	spin_acquire(&lock->dep_map, subclass, 0, _RET_IP_);
+	_raw_spin_lock(lock);
+}
+
+EXPORT_SYMBOL(_spin_lock_nested);
+
+#endif
+
 void __lockfunc _spin_unlock(spinlock_t *lock)
 {
+	spin_release(&lock->dep_map, 1, _RET_IP_);
 	_raw_spin_unlock(lock);
 	preempt_enable();
 }
@@ -264,6 +312,7 @@ EXPORT_SYMBOL(_spin_unlock);
 
 void __lockfunc _write_unlock(rwlock_t *lock)
 {
+	rwlock_release(&lock->dep_map, 1, _RET_IP_);
 	_raw_write_unlock(lock);
 	preempt_enable();
 }
@@ -271,6 +320,7 @@ EXPORT_SYMBOL(_write_unlock);
 
 void __lockfunc _read_unlock(rwlock_t *lock)
 {
+	rwlock_release(&lock->dep_map, 1, _RET_IP_);
 	_raw_read_unlock(lock);
 	preempt_enable();
 }
@@ -278,6 +328,7 @@ EXPORT_SYMBOL(_read_unlock);
 
 void __lockfunc _spin_unlock_irqrestore(spinlock_t *lock, unsigned long flags)
 {
+	spin_release(&lock->dep_map, 1, _RET_IP_);
 	_raw_spin_unlock(lock);
 	local_irq_restore(flags);
 	preempt_enable();
@@ -286,6 +337,7 @@ EXPORT_SYMBOL(_spin_unlock_irqrestore);
 
 void __lockfunc _spin_unlock_irq(spinlock_t *lock)
 {
+	spin_release(&lock->dep_map, 1, _RET_IP_);
 	_raw_spin_unlock(lock);
 	local_irq_enable();
 	preempt_enable();
@@ -294,14 +346,16 @@ EXPORT_SYMBOL(_spin_unlock_irq);
 
 void __lockfunc _spin_unlock_bh(spinlock_t *lock)
 {
+	spin_release(&lock->dep_map, 1, _RET_IP_);
 	_raw_spin_unlock(lock);
 	preempt_enable_no_resched();
-	local_bh_enable();
+	local_bh_enable_ip((unsigned long)__builtin_return_address(0));
 }
 EXPORT_SYMBOL(_spin_unlock_bh);
 
 void __lockfunc _read_unlock_irqrestore(rwlock_t *lock, unsigned long flags)
 {
+	rwlock_release(&lock->dep_map, 1, _RET_IP_);
 	_raw_read_unlock(lock);
 	local_irq_restore(flags);
 	preempt_enable();
@@ -310,6 +364,7 @@ EXPORT_SYMBOL(_read_unlock_irqrestore);
 
 void __lockfunc _read_unlock_irq(rwlock_t *lock)
 {
+	rwlock_release(&lock->dep_map, 1, _RET_IP_);
 	_raw_read_unlock(lock);
 	local_irq_enable();
 	preempt_enable();
@@ -318,14 +373,16 @@ EXPORT_SYMBOL(_read_unlock_irq);
 
 void __lockfunc _read_unlock_bh(rwlock_t *lock)
 {
+	rwlock_release(&lock->dep_map, 1, _RET_IP_);
 	_raw_read_unlock(lock);
 	preempt_enable_no_resched();
-	local_bh_enable();
+	local_bh_enable_ip((unsigned long)__builtin_return_address(0));
 }
 EXPORT_SYMBOL(_read_unlock_bh);
 
 void __lockfunc _write_unlock_irqrestore(rwlock_t *lock, unsigned long flags)
 {
+	rwlock_release(&lock->dep_map, 1, _RET_IP_);
 	_raw_write_unlock(lock);
 	local_irq_restore(flags);
 	preempt_enable();
@@ -334,6 +391,7 @@ EXPORT_SYMBOL(_write_unlock_irqrestore);
 
 void __lockfunc _write_unlock_irq(rwlock_t *lock)
 {
+	rwlock_release(&lock->dep_map, 1, _RET_IP_);
 	_raw_write_unlock(lock);
 	local_irq_enable();
 	preempt_enable();
@@ -342,9 +400,10 @@ EXPORT_SYMBOL(_write_unlock_irq);
 
 void __lockfunc _write_unlock_bh(rwlock_t *lock)
 {
+	rwlock_release(&lock->dep_map, 1, _RET_IP_);
 	_raw_write_unlock(lock);
 	preempt_enable_no_resched();
-	local_bh_enable();
+	local_bh_enable_ip((unsigned long)__builtin_return_address(0));
 }
 EXPORT_SYMBOL(_write_unlock_bh);
 
@@ -352,11 +411,13 @@ int __lockfunc _spin_trylock_bh(spinlock_t *lock)
 {
 	local_bh_disable();
 	preempt_disable();
-	if (_raw_spin_trylock(lock))
+	if (_raw_spin_trylock(lock)) {
+		spin_acquire(&lock->dep_map, 0, 1, _RET_IP_);
 		return 1;
+	}
 
 	preempt_enable_no_resched();
-	local_bh_enable();
+	local_bh_enable_ip((unsigned long)__builtin_return_address(0));
 	return 0;
 }
 EXPORT_SYMBOL(_spin_trylock_bh);