1 files changed, 302 insertions, 0 deletions
diff --git a/kernel/locking/spinlock_debug.c b/kernel/locking/spinlock_debug.c
new file mode 100644
index 000000000000..0374a596cffa
--- /dev/null
+++ b/kernel/locking/spinlock_debug.c
@@ -0,0 +1,302 @@
+/*
+ * Copyright 2005, Red Hat, Inc., Ingo Molnar
+ * Released under the General Public License (GPL).
+ *
+ * This file contains the spinlock/rwlock implementations for
+ * DEBUG_SPINLOCK.
+ */
+
+#include <linux/spinlock.h>
+#include <linux/nmi.h>
+#include <linux/interrupt.h>
+#include <linux/debug_locks.h>
+#include <linux/delay.h>
+#include <linux/export.h>
+
+void __raw_spin_lock_init(raw_spinlock_t *lock, const char *name,
+			  struct lock_class_key *key)
+{
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+	/*
+	 * Make sure we are not reinitializing a held lock:
+	 */
+	debug_check_no_locks_freed((void *)lock, sizeof(*lock));
+	lockdep_init_map(&lock->dep_map, name, key, 0);
+#endif
+	lock->raw_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
+	lock->magic = SPINLOCK_MAGIC;
+	lock->owner = SPINLOCK_OWNER_INIT;
+	lock->owner_cpu = -1;
+}
+
+EXPORT_SYMBOL(__raw_spin_lock_init);
+
+void __rwlock_init(rwlock_t *lock, const char *name,
+		   struct lock_class_key *key)
+{
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+	/*
+	 * Make sure we are not reinitializing a held lock:
+	 */
+	debug_check_no_locks_freed((void *)lock, sizeof(*lock));
+	lockdep_init_map(&lock->dep_map, name, key, 0);
+#endif
+	lock->raw_lock = (arch_rwlock_t) __ARCH_RW_LOCK_UNLOCKED;
+	lock->magic = RWLOCK_MAGIC;
+	lock->owner = SPINLOCK_OWNER_INIT;
+	lock->owner_cpu = -1;
+}
+
+EXPORT_SYMBOL(__rwlock_init);
+
+static void spin_dump(raw_spinlock_t *lock, const char *msg)
+{
+	struct task_struct *owner = NULL;
+
+	if (lock->owner && lock->owner != SPINLOCK_OWNER_INIT)
+		owner = lock->owner;
+	printk(KERN_EMERG "BUG: spinlock %s on CPU#%d, %s/%d\n",
+		msg, raw_smp_processor_id(),
+		current->comm, task_pid_nr(current));
+	printk(KERN_EMERG " lock: %pS, .magic: %08x, .owner: %s/%d, "
+			".owner_cpu: %d\n",
+		lock, lock->magic,
+		owner ? owner->comm : "<none>",
+		owner ? task_pid_nr(owner) : -1,
+		lock->owner_cpu);
+	dump_stack();
+}
+
+static void spin_bug(raw_spinlock_t *lock, const char *msg)
+{
+	if (!debug_locks_off())
+		return;
+
+	spin_dump(lock, msg);
+}
+
+#define SPIN_BUG_ON(cond, lock, msg) if (unlikely(cond)) spin_bug(lock, msg)
+
+static inline void
+debug_spin_lock_before(raw_spinlock_t *lock)
+{
+	SPIN_BUG_ON(lock->magic != SPINLOCK_MAGIC, lock, "bad magic");
+	SPIN_BUG_ON(lock->owner == current, lock, "recursion");
+	SPIN_BUG_ON(lock->owner_cpu == raw_smp_processor_id(),
+							lock, "cpu recursion");
+}
+
+static inline void debug_spin_lock_after(raw_spinlock_t *lock)
+{
+	lock->owner_cpu = raw_smp_processor_id();
+	lock->owner = current;
+}
+
+static inline void debug_spin_unlock(raw_spinlock_t *lock)
+{
+	SPIN_BUG_ON(lock->magic != SPINLOCK_MAGIC, lock, "bad magic");
+	SPIN_BUG_ON(!raw_spin_is_locked(lock), lock, "already unlocked");
+	SPIN_BUG_ON(lock->owner != current, lock, "wrong owner");
+	SPIN_BUG_ON(lock->owner_cpu != raw_smp_processor_id(),
+							lock, "wrong CPU");
+	lock->owner = SPINLOCK_OWNER_INIT;
+	lock->owner_cpu = -1;
+}
+
+static void __spin_lock_debug(raw_spinlock_t *lock)
+{
+	u64 i;
+	u64 loops = loops_per_jiffy * HZ;
+
+	for (i = 0; i < loops; i++) {
+		if (arch_spin_trylock(&lock->raw_lock))
+			return;
+		__delay(1);
+	}
+	/* lockup suspected: */
+	spin_dump(lock, "lockup suspected");
+#ifdef CONFIG_SMP
+	trigger_all_cpu_backtrace();
+#endif
+
+	/*
+	 * The trylock above was causing a livelock.  Give the lower level arch
+	 * specific lock code a chance to acquire the lock. We have already
+	 * printed a warning/backtrace at this point. The non-debug arch
+	 * specific code might actually succeed in acquiring the lock.  If it is
+	 * not successful, the end-result is the same - there is no forward
+	 * progress.
+	 */
+	arch_spin_lock(&lock->raw_lock);
+}
+
+void do_raw_spin_lock(raw_spinlock_t *lock)
+{
+	debug_spin_lock_before(lock);
+	if (unlikely(!arch_spin_trylock(&lock->raw_lock)))
+		__spin_lock_debug(lock);
+	debug_spin_lock_after(lock);
+}
+
+int do_raw_spin_trylock(raw_spinlock_t *lock)
+{
+	int ret = arch_spin_trylock(&lock->raw_lock);
+
+	if (ret)
+		debug_spin_lock_after(lock);
+#ifndef CONFIG_SMP
+	/*
+	 * Must not happen on UP:
+	 */
+	SPIN_BUG_ON(!ret, lock, "trylock failure on UP");
+#endif
+	return ret;
+}
+
+void do_raw_spin_unlock(raw_spinlock_t *lock)
+{
+	debug_spin_unlock(lock);
+	arch_spin_unlock(&lock->raw_lock);
+}
+
+static void rwlock_bug(rwlock_t *lock, const char *msg)
+{
+	if (!debug_locks_off())
+		return;
+
+	printk(KERN_EMERG "BUG: rwlock %s on CPU#%d, %s/%d, %p\n",
+		msg, raw_smp_processor_id(), current->comm,
+		task_pid_nr(current), lock);
+	dump_stack();
+}
+
+#define RWLOCK_BUG_ON(cond, lock, msg) if (unlikely(cond)) rwlock_bug(lock, msg)
+
+#if 0		/* __write_lock_debug() can lock up - maybe this can too? */
+static void __read_lock_debug(rwlock_t *lock)
+{
+	u64 i;
+	u64 loops = loops_per_jiffy * HZ;
+	int print_once = 1;
+
+	for (;;) {
+		for (i = 0; i < loops; i++) {
+			if (arch_read_trylock(&lock->raw_lock))
+				return;
+			__delay(1);
+		}
+		/* lockup suspected: */
+		if (print_once) {
+			print_once = 0;
+			printk(KERN_EMERG "BUG: read-lock lockup on CPU#%d, "
+					"%s/%d, %p\n",
+				raw_smp_processor_id(), current->comm,
+				current->pid, lock);
+			dump_stack();
+		}
+	}
+}
+#endif
+
+void do_raw_read_lock(rwlock_t *lock)
+{
+	RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");
+	arch_read_lock(&lock->raw_lock);
+}
+
+int do_raw_read_trylock(rwlock_t *lock)
+{
+	int ret = arch_read_trylock(&lock->raw_lock);
+
+#ifndef CONFIG_SMP
+	/*
+	 * Must not happen on UP:
+	 */
+	RWLOCK_BUG_ON(!ret, lock, "trylock failure on UP");
+#endif
+	return ret;
+}
+
+void do_raw_read_unlock(rwlock_t *lock)
+{
+	RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");
+	arch_read_unlock(&lock->raw_lock);
+}
+
+static inline void debug_write_lock_before(rwlock_t *lock)
+{
+	RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");
+	RWLOCK_BUG_ON(lock->owner == current, lock, "recursion");
+	RWLOCK_BUG_ON(lock->owner_cpu == raw_smp_processor_id(),
+							lock, "cpu recursion");
+}
+
+static inline void debug_write_lock_after(rwlock_t *lock)
+{
+	lock->owner_cpu = raw_smp_processor_id();
+	lock->owner = current;
+}
+
+static inline void debug_write_unlock(rwlock_t *lock)
+{
+	RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");
+	RWLOCK_BUG_ON(lock->owner != current, lock, "wrong owner");
+	RWLOCK_BUG_ON(lock->owner_cpu != raw_smp_processor_id(),
+							lock, "wrong CPU");
+	lock->owner = SPINLOCK_OWNER_INIT;
+	lock->owner_cpu = -1;
+}
+
+#if 0		/* This can cause lockups */
+static void __write_lock_debug(rwlock_t *lock)
+{
+	u64 i;
+	u64 loops = loops_per_jiffy * HZ;
+	int print_once = 1;
+
+	for (;;) {
+		for (i = 0; i < loops; i++) {
+			if (arch_write_trylock(&lock->raw_lock))
+				return;
+			__delay(1);
+		}
+		/* lockup suspected: */
+		if (print_once) {
+			print_once = 0;
+			printk(KERN_EMERG "BUG: write-lock lockup on CPU#%d, "
+					"%s/%d, %p\n",
+				raw_smp_processor_id(), current->comm,
+				current->pid, lock);
+			dump_stack();
+		}
+	}
+}
+#endif
+
+void do_raw_write_lock(rwlock_t *lock)
+{
+	debug_write_lock_before(lock);
+	arch_write_lock(&lock->raw_lock);
+	debug_write_lock_after(lock);
+}
+
+int do_raw_write_trylock(rwlock_t *lock)
+{
+	int ret = arch_write_trylock(&lock->raw_lock);
+
+	if (ret)
+		debug_write_lock_after(lock);
+#ifndef CONFIG_SMP
+	/*
+	 * Must not happen on UP:
+	 */
+	RWLOCK_BUG_ON(!ret, lock, "trylock failure on UP");
+#endif
+	return ret;
+}
+
+void do_raw_write_unlock(rwlock_t *lock)
+{
+	debug_write_unlock(lock);
+	arch_write_unlock(&lock->raw_lock);
+}