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authorAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
committerAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
commit57f0f512b273f60d52568b8c6b77e17f5636edc0 (patch)
tree5e910f0e82173f4ef4f51111366a3f1299037a7b /kernel/locking/mutex-debug.c
Initial import
Diffstat (limited to 'kernel/locking/mutex-debug.c')
-rw-r--r--kernel/locking/mutex-debug.c120
1 files changed, 120 insertions, 0 deletions
diff --git a/kernel/locking/mutex-debug.c b/kernel/locking/mutex-debug.c
new file mode 100644
index 000000000..3ef373600
--- /dev/null
+++ b/kernel/locking/mutex-debug.c
@@ -0,0 +1,120 @@
+/*
+ * kernel/mutex-debug.c
+ *
+ * Debugging code for mutexes
+ *
+ * Started by Ingo Molnar:
+ *
+ * Copyright (C) 2004, 2005, 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
+ *
+ * lock debugging, locking tree, deadlock detection started by:
+ *
+ * Copyright (C) 2004, LynuxWorks, Inc., Igor Manyilov, Bill Huey
+ * Released under the General Public License (GPL).
+ */
+#include <linux/mutex.h>
+#include <linux/delay.h>
+#include <linux/export.h>
+#include <linux/poison.h>
+#include <linux/sched.h>
+#include <linux/spinlock.h>
+#include <linux/kallsyms.h>
+#include <linux/interrupt.h>
+#include <linux/debug_locks.h>
+
+#include "mutex-debug.h"
+
+/*
+ * Must be called with lock->wait_lock held.
+ */
+void debug_mutex_lock_common(struct mutex *lock, struct mutex_waiter *waiter)
+{
+ memset(waiter, MUTEX_DEBUG_INIT, sizeof(*waiter));
+ waiter->magic = waiter;
+ INIT_LIST_HEAD(&waiter->list);
+}
+
+void debug_mutex_wake_waiter(struct mutex *lock, struct mutex_waiter *waiter)
+{
+ SMP_DEBUG_LOCKS_WARN_ON(!spin_is_locked(&lock->wait_lock));
+ DEBUG_LOCKS_WARN_ON(list_empty(&lock->wait_list));
+ DEBUG_LOCKS_WARN_ON(waiter->magic != waiter);
+ DEBUG_LOCKS_WARN_ON(list_empty(&waiter->list));
+}
+
+void debug_mutex_free_waiter(struct mutex_waiter *waiter)
+{
+ DEBUG_LOCKS_WARN_ON(!list_empty(&waiter->list));
+ memset(waiter, MUTEX_DEBUG_FREE, sizeof(*waiter));
+}
+
+void debug_mutex_add_waiter(struct mutex *lock, struct mutex_waiter *waiter,
+ struct thread_info *ti)
+{
+ SMP_DEBUG_LOCKS_WARN_ON(!spin_is_locked(&lock->wait_lock));
+
+ /* Mark the current thread as blocked on the lock: */
+ ti->task->blocked_on = waiter;
+}
+
+void mutex_remove_waiter(struct mutex *lock, struct mutex_waiter *waiter,
+ struct thread_info *ti)
+{
+ DEBUG_LOCKS_WARN_ON(list_empty(&waiter->list));
+ DEBUG_LOCKS_WARN_ON(waiter->task != ti->task);
+ DEBUG_LOCKS_WARN_ON(ti->task->blocked_on != waiter);
+ ti->task->blocked_on = NULL;
+
+ list_del_init(&waiter->list);
+ waiter->task = NULL;
+}
+
+void debug_mutex_unlock(struct mutex *lock)
+{
+ if (likely(debug_locks)) {
+ DEBUG_LOCKS_WARN_ON(lock->magic != lock);
+
+ if (!lock->owner)
+ DEBUG_LOCKS_WARN_ON(!lock->owner);
+ else
+ DEBUG_LOCKS_WARN_ON(lock->owner != current);
+
+ DEBUG_LOCKS_WARN_ON(!lock->wait_list.prev && !lock->wait_list.next);
+ }
+
+ /*
+ * __mutex_slowpath_needs_to_unlock() is explicitly 0 for debug
+ * mutexes so that we can do it here after we've verified state.
+ */
+ mutex_clear_owner(lock);
+ atomic_set(&lock->count, 1);
+}
+
+void debug_mutex_init(struct mutex *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->magic = lock;
+}
+
+/***
+ * mutex_destroy - mark a mutex unusable
+ * @lock: the mutex to be destroyed
+ *
+ * This function marks the mutex uninitialized, and any subsequent
+ * use of the mutex is forbidden. The mutex must not be locked when
+ * this function is called.
+ */
+void mutex_destroy(struct mutex *lock)
+{
+ DEBUG_LOCKS_WARN_ON(mutex_is_locked(lock));
+ lock->magic = NULL;
+}
+
+EXPORT_SYMBOL_GPL(mutex_destroy);