[GitHub/mt8127/android_kernel_alcatel_ttab.git] / kernel / mutex-debug.c

/*
 * 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/sched.h>
#include <linux/delay.h>
#include <linux/module.h>
#include <linux/spinlock.h>
#include <linux/kallsyms.h>
#include <linux/interrupt.h>

#include <asm/mutex.h>

#include "mutex-debug.h"

/*
 * We need a global lock when we walk through the multi-process
 * lock tree. Only used in the deadlock-debugging case.
 */
DEFINE_SPINLOCK(debug_mutex_lock);

/*
 * All locks held by all tasks, in a single global list:
 */
LIST_HEAD(debug_mutex_held_locks);

/*
 * In the debug case we carry the caller's instruction pointer into
 * other functions, but we dont want the function argument overhead
 * in the nondebug case - hence these macros:
 */
#define __IP_DECL__		, unsigned long ip
#define __IP__			, ip
#define __RET_IP__		, (unsigned long)__builtin_return_address(0)

/*
 * "mutex debugging enabled" flag. We turn it off when we detect
 * the first problem because we dont want to recurse back
 * into the tracing code when doing error printk or
 * executing a BUG():
 */
int debug_mutex_on = 1;

static void printk_task(struct task_struct *p)
{
	if (p)
		printk("%16s:%5d [%p, %3d]", p->comm, p->pid, p, p->prio);
	else
		printk("<none>");
}

static void printk_ti(struct thread_info *ti)
{
	if (ti)
		printk_task(ti->task);
	else
		printk("<none>");
}

static void printk_task_short(struct task_struct *p)
{
	if (p)
		printk("%s/%d [%p, %3d]", p->comm, p->pid, p, p->prio);
	else
		printk("<none>");
}

static void printk_lock(struct mutex *lock, int print_owner)
{
	printk(" [%p] {%s}\n", lock, lock->name);

	if (print_owner && lock->owner) {
		printk(".. held by:  ");
		printk_ti(lock->owner);
		printk("\n");
	}
	if (lock->owner) {
		printk("... acquired at:               ");
		print_symbol("%s\n", lock->acquire_ip);
	}
}

/*
 * printk locks held by a task:
 */
static void show_task_locks(struct task_struct *p)
{
	switch (p->state) {
	case TASK_RUNNING:		printk("R"); break;
	case TASK_INTERRUPTIBLE:	printk("S"); break;
	case TASK_UNINTERRUPTIBLE:	printk("D"); break;
	case TASK_STOPPED:		printk("T"); break;
	case EXIT_ZOMBIE:		printk("Z"); break;
	case EXIT_DEAD:			printk("X"); break;
	default:			printk("?"); break;
	}
	printk_task(p);
	if (p->blocked_on) {
		struct mutex *lock = p->blocked_on->lock;

		printk(" blocked on mutex:");
		printk_lock(lock, 1);
	} else
		printk(" (not blocked on mutex)\n");
}

/*
 * printk all locks held in the system (if filter == NULL),
 * or all locks belonging to a single task (if filter != NULL):
 */
void show_held_locks(struct task_struct *filter)
{
	struct list_head *curr, *cursor = NULL;
	struct mutex *lock;
	struct thread_info *t;
	unsigned long flags;
	int count = 0;

	if (filter) {
		printk("------------------------------\n");
		printk("| showing all locks held by: |  (");
		printk_task_short(filter);
		printk("):\n");
		printk("------------------------------\n");
	} else {
		printk("---------------------------\n");
		printk("| showing all locks held: |\n");
		printk("---------------------------\n");
	}

	/*
	 * Play safe and acquire the global trace lock. We
	 * cannot printk with that lock held so we iterate
	 * very carefully:
	 */
next:
	debug_spin_lock_save(&debug_mutex_lock, flags);
	list_for_each(curr, &debug_mutex_held_locks) {
		if (cursor && curr != cursor)
			continue;
		lock = list_entry(curr, struct mutex, held_list);
		t = lock->owner;
		if (filter && (t != filter->thread_info))
			continue;
		count++;
		cursor = curr->next;
		debug_spin_lock_restore(&debug_mutex_lock, flags);

		printk("\n#%03d:            ", count);
		printk_lock(lock, filter ? 0 : 1);
		goto next;
	}
	debug_spin_lock_restore(&debug_mutex_lock, flags);
	printk("\n");
}

void mutex_debug_show_all_locks(void)
{
	struct task_struct *g, *p;
	int count = 10;
	int unlock = 1;

	printk("\nShowing all blocking locks in the system:\n");

	/*
	 * Here we try to get the tasklist_lock as hard as possible,
	 * if not successful after 2 seconds we ignore it (but keep
	 * trying). This is to enable a debug printout even if a
	 * tasklist_lock-holding task deadlocks or crashes.
	 */
retry:
	if (!read_trylock(&tasklist_lock)) {
		if (count == 10)
			printk("hm, tasklist_lock locked, retrying... ");
		if (count) {
			count--;
			printk(" #%d", 10-count);
			mdelay(200);
			goto retry;
		}
		printk(" ignoring it.\n");
		unlock = 0;
	}
	if (count != 10)
		printk(" locked it.\n");

	do_each_thread(g, p) {
		show_task_locks(p);
		if (!unlock)
			if (read_trylock(&tasklist_lock))
				unlock = 1;
	} while_each_thread(g, p);

	printk("\n");
	show_held_locks(NULL);
	printk("=============================================\n\n");

	if (unlock)
		read_unlock(&tasklist_lock);
}

static void report_deadlock(struct task_struct *task, struct mutex *lock,
			    struct mutex *lockblk, unsigned long ip)
{
	printk("\n%s/%d is trying to acquire this lock:\n",
		current->comm, current->pid);
	printk_lock(lock, 1);
	printk("... trying at:                 ");
	print_symbol("%s\n", ip);
	show_held_locks(current);

	if (lockblk) {
		printk("but %s/%d is deadlocking current task %s/%d!\n\n",
			task->comm, task->pid, current->comm, current->pid);
		printk("\n%s/%d is blocked on this lock:\n",
			task->comm, task->pid);
		printk_lock(lockblk, 1);

		show_held_locks(task);

		printk("\n%s/%d's [blocked] stackdump:\n\n",
			task->comm, task->pid);
		show_stack(task, NULL);
	}

	printk("\n%s/%d's [current] stackdump:\n\n",
		current->comm, current->pid);
	dump_stack();
	mutex_debug_show_all_locks();
	printk("[ turning off deadlock detection. Please report this. ]\n\n");
	local_irq_disable();
}

/*
 * Recursively check for mutex deadlocks:
 */
static int check_deadlock(struct mutex *lock, int depth,
			  struct thread_info *ti, unsigned long ip)
{
	struct mutex *lockblk;
	struct task_struct *task;

	if (!debug_mutex_on)
		return 0;

	ti = lock->owner;
	if (!ti)
		return 0;

	task = ti->task;
	lockblk = NULL;
	if (task->blocked_on)
		lockblk = task->blocked_on->lock;

	/* Self-deadlock: */
	if (current == task) {
		DEBUG_OFF();
		if (depth)
			return 1;
		printk("\n==========================================\n");
		printk(  "[ BUG: lock recursion deadlock detected! |\n");
		printk(  "------------------------------------------\n");
		report_deadlock(task, lock, NULL, ip);
		return 0;
	}

	/* Ugh, something corrupted the lock data structure? */
	if (depth > 20) {
		DEBUG_OFF();
		printk("\n===========================================\n");
		printk(  "[ BUG: infinite lock dependency detected!? |\n");
		printk(  "-------------------------------------------\n");
		report_deadlock(task, lock, lockblk, ip);
		return 0;
	}

	/* Recursively check for dependencies: */
	if (lockblk && check_deadlock(lockblk, depth+1, ti, ip)) {
		printk("\n============================================\n");
		printk(  "[ BUG: circular locking deadlock detected! ]\n");
		printk(  "--------------------------------------------\n");
		report_deadlock(task, lock, lockblk, ip);
		return 0;
	}
	return 0;
}

/*
 * Called when a task exits, this function checks whether the
 * task is holding any locks, and reports the first one if so:
 */
void mutex_debug_check_no_locks_held(struct task_struct *task)
{
	struct list_head *curr, *next;
	struct thread_info *t;
	unsigned long flags;
	struct mutex *lock;

	if (!debug_mutex_on)
		return;

	debug_spin_lock_save(&debug_mutex_lock, flags);
	list_for_each_safe(curr, next, &debug_mutex_held_locks) {
		lock = list_entry(curr, struct mutex, held_list);
		t = lock->owner;
		if (t != task->thread_info)
			continue;
		list_del_init(curr);
		DEBUG_OFF();
		debug_spin_lock_restore(&debug_mutex_lock, flags);

		printk("BUG: %s/%d, lock held at task exit time!\n",
			task->comm, task->pid);
		printk_lock(lock, 1);
		if (lock->owner != task->thread_info)
			printk("exiting task is not even the owner??\n");
		return;
	}
	debug_spin_lock_restore(&debug_mutex_lock, flags);
}

/*
 * Called when kernel memory is freed (or unmapped), or if a mutex
 * is destroyed or reinitialized - this code checks whether there is
 * any held lock in the memory range of <from> to <to>:
 */
void mutex_debug_check_no_locks_freed(const void *from, const void *to)
{
	struct list_head *curr, *next;
	unsigned long flags;
	struct mutex *lock;
	void *lock_addr;

	if (!debug_mutex_on)
		return;

	debug_spin_lock_save(&debug_mutex_lock, flags);
	list_for_each_safe(curr, next, &debug_mutex_held_locks) {
		lock = list_entry(curr, struct mutex, held_list);
		lock_addr = lock;
		if (lock_addr < from || lock_addr >= to)
			continue;
		list_del_init(curr);
		DEBUG_OFF();
		debug_spin_lock_restore(&debug_mutex_lock, flags);

		printk("BUG: %s/%d, active lock [%p(%p-%p)] freed!\n",
			current->comm, current->pid, lock, from, to);
		dump_stack();
		printk_lock(lock, 1);
		if (lock->owner != current_thread_info())
			printk("freeing task is not even the owner??\n");
		return;
	}
	debug_spin_lock_restore(&debug_mutex_lock, flags);
}

/*
 * Must be called with lock->wait_lock held.
 */
void debug_mutex_set_owner(struct mutex *lock,
			   struct thread_info *new_owner __IP_DECL__)
{
	lock->owner = new_owner;
	DEBUG_WARN_ON(!list_empty(&lock->held_list));
	if (debug_mutex_on) {
		list_add_tail(&lock->held_list, &debug_mutex_held_locks);
		lock->acquire_ip = ip;
	}
}

void debug_mutex_init_waiter(struct mutex_waiter *waiter)
{
	memset(waiter, 0x11, sizeof(*waiter));
	waiter->magic = waiter;
	INIT_LIST_HEAD(&waiter->list);
}

void debug_mutex_wake_waiter(struct mutex *lock, struct mutex_waiter *waiter)
{
	SMP_DEBUG_WARN_ON(!spin_is_locked(&lock->wait_lock));
	DEBUG_WARN_ON(list_empty(&lock->wait_list));
	DEBUG_WARN_ON(waiter->magic != waiter);
	DEBUG_WARN_ON(list_empty(&waiter->list));
}

void debug_mutex_free_waiter(struct mutex_waiter *waiter)
{
	DEBUG_WARN_ON(!list_empty(&waiter->list));
	memset(waiter, 0x22, sizeof(*waiter));
}

void debug_mutex_add_waiter(struct mutex *lock, struct mutex_waiter *waiter,
			    struct thread_info *ti __IP_DECL__)
{
	SMP_DEBUG_WARN_ON(!spin_is_locked(&lock->wait_lock));
	check_deadlock(lock, 0, ti, ip);
	/* Mark the current thread as blocked on the lock: */
	ti->task->blocked_on = waiter;
	waiter->lock = lock;
}

void mutex_remove_waiter(struct mutex *lock, struct mutex_waiter *waiter,
			 struct thread_info *ti)
{
	DEBUG_WARN_ON(list_empty(&waiter->list));
	DEBUG_WARN_ON(waiter->task != ti->task);
	DEBUG_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)
{
	DEBUG_WARN_ON(lock->magic != lock);
	DEBUG_WARN_ON(!lock->wait_list.prev && !lock->wait_list.next);
	DEBUG_WARN_ON(lock->owner != current_thread_info());
	if (debug_mutex_on) {
		DEBUG_WARN_ON(list_empty(&lock->held_list));
		list_del_init(&lock->held_list);
	}
}

void debug_mutex_init(struct mutex *lock, const char *name)
{
	/*
	 * Make sure we are not reinitializing a held lock:
	 */
	mutex_debug_check_no_locks_freed((void *)lock, (void *)(lock + 1));
	lock->owner = NULL;
	INIT_LIST_HEAD(&lock->held_list);
	lock->name = name;
	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 fastcall mutex_destroy(struct mutex *lock)
{
	DEBUG_WARN_ON(mutex_is_locked(lock));
	lock->magic = NULL;
}

EXPORT_SYMBOL_GPL(mutex_destroy);
Commit	Line	Data
408894ee IM	1	/*
	2	* kernel/mutex-debug.c
	3	*
	4	* Debugging code for mutexes
	5	*
	6	* Started by Ingo Molnar:
	7	*
	8	* Copyright (C) 2004, 2005, 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
	9	*
	10	* lock debugging, locking tree, deadlock detection started by:
	11	*
	12	* Copyright (C) 2004, LynuxWorks, Inc., Igor Manyilov, Bill Huey
	13	* Released under the General Public License (GPL).
	14	*/
	15	#include <linux/mutex.h>
	16	#include <linux/sched.h>
	17	#include <linux/delay.h>
	18	#include <linux/module.h>
	19	#include <linux/spinlock.h>
	20	#include <linux/kallsyms.h>
	21	#include <linux/interrupt.h>
	22
	23	#include <asm/mutex.h>
	24
	25	#include "mutex-debug.h"
	26
	27	/*
	28	* We need a global lock when we walk through the multi-process
	29	* lock tree. Only used in the deadlock-debugging case.
	30	*/
	31	DEFINE_SPINLOCK(debug_mutex_lock);
	32
	33	/*
	34	* All locks held by all tasks, in a single global list:
	35	*/
	36	LIST_HEAD(debug_mutex_held_locks);
	37
	38	/*
	39	* In the debug case we carry the caller's instruction pointer into
	40	* other functions, but we dont want the function argument overhead
	41	* in the nondebug case - hence these macros:
	42	*/
	43	#define __IP_DECL__ , unsigned long ip
	44	#define __IP__ , ip
	45	#define __RET_IP__ , (unsigned long)__builtin_return_address(0)
	46
	47	/*
	48	* "mutex debugging enabled" flag. We turn it off when we detect
	49	* the first problem because we dont want to recurse back
	50	* into the tracing code when doing error printk or
	51	* executing a BUG():
	52	*/
	53	int debug_mutex_on = 1;
	54
	55	static void printk_task(struct task_struct *p)
	56	{
	57	if (p)
	58	printk("%16s:%5d [%p, %3d]", p->comm, p->pid, p, p->prio);
	59	else
	60	printk("<none>");
	61	}
	62
	63	static void printk_ti(struct thread_info *ti)
	64	{
65	if (ti)
66	printk_task(ti->task);
67	else
68	printk("<none>");
69	}
70
71	static void printk_task_short(struct task_struct *p)
72	{
73	if (p)
74	printk("%s/%d [%p, %3d]", p->comm, p->pid, p, p->prio);
75	else
76	printk("<none>");
77	}
78
79	static void printk_lock(struct mutex *lock, int print_owner)
80	{
81	printk(" [%p] {%s}\n", lock, lock->name);
82
83	if (print_owner && lock->owner) {
84	printk(".. held by: ");
85	printk_ti(lock->owner);
86	printk("\n");
87	}
88	if (lock->owner) {
89	printk("... acquired at: ");
90	print_symbol("%s\n", lock->acquire_ip);
91	}
92	}
93
94	/*
95	* printk locks held by a task:
96	*/
97	static void show_task_locks(struct task_struct *p)
98	{
99	switch (p->state) {
100	case TASK_RUNNING: printk("R"); break;
101	case TASK_INTERRUPTIBLE: printk("S"); break;
102	case TASK_UNINTERRUPTIBLE: printk("D"); break;
103	case TASK_STOPPED: printk("T"); break;
104	case EXIT_ZOMBIE: printk("Z"); break;
105	case EXIT_DEAD: printk("X"); break;
106	default: printk("?"); break;
107	}
108	printk_task(p);
109	if (p->blocked_on) {
110	struct mutex *lock = p->blocked_on->lock;
111
112	printk(" blocked on mutex:");
113	printk_lock(lock, 1);
114	} else
115	printk(" (not blocked on mutex)\n");
116	}
117
118	/*
119	* printk all locks held in the system (if filter == NULL),
120	* or all locks belonging to a single task (if filter != NULL):
121	*/
122	void show_held_locks(struct task_struct *filter)
123	{
124	struct list_head curr, cursor = NULL;
125	struct mutex *lock;
126	struct thread_info *t;
127	unsigned long flags;
128	int count = 0;
129
130	if (filter) {
131	printk("------------------------------\n");
132	printk("\| showing all locks held by: \| (");
133	printk_task_short(filter);
134	printk("):\n");
135	printk("------------------------------\n");
136	} else {
137	printk("---------------------------\n");
138	printk("\| showing all locks held: \|\n");
139	printk("---------------------------\n");
140	}
141
142	/*
143	* Play safe and acquire the global trace lock. We
144	* cannot printk with that lock held so we iterate
145	* very carefully:
146	*/
147	next:
148	debug_spin_lock_save(&debug_mutex_lock, flags);
149	list_for_each(curr, &debug_mutex_held_locks) {
150	if (cursor && curr != cursor)
151	continue;
152	lock = list_entry(curr, struct mutex, held_list);
153	t = lock->owner;
154	if (filter && (t != filter->thread_info))
155	continue;
156	count++;
157	cursor = curr->next;
158	debug_spin_lock_restore(&debug_mutex_lock, flags);
159
160	printk("\n#%03d: ", count);
161	printk_lock(lock, filter ? 0 : 1);
162	goto next;
163	}
164	debug_spin_lock_restore(&debug_mutex_lock, flags);
165	printk("\n");
166	}
167
168	void mutex_debug_show_all_locks(void)
169	{
170	struct task_struct g, p;
171	int count = 10;
172	int unlock = 1;
173
174	printk("\nShowing all blocking locks in the system:\n");
175
176	/*
177	* Here we try to get the tasklist_lock as hard as possible,
178	* if not successful after 2 seconds we ignore it (but keep
179	* trying). This is to enable a debug printout even if a
180	* tasklist_lock-holding task deadlocks or crashes.
181	*/
182	retry:
183	if (!read_trylock(&tasklist_lock)) {
184	if (count == 10)
185	printk("hm, tasklist_lock locked, retrying... ");
186	if (count) {
187	count--;
188	printk(" #%d", 10-count);
189	mdelay(200);
190	goto retry;
191	}
192	printk(" ignoring it.\n");
193	unlock = 0;
194	}
195	if (count != 10)
196	printk(" locked it.\n");
197
198	do_each_thread(g, p) {
199	show_task_locks(p);
200	if (!unlock)
201	if (read_trylock(&tasklist_lock))
202	unlock = 1;
203	} while_each_thread(g, p);
204
205	printk("\n");
206	show_held_locks(NULL);
207	printk("=============================================\n\n");
208
209	if (unlock)
210	read_unlock(&tasklist_lock);
211	}
212
213	static void report_deadlock(struct task_struct task, struct mutex lock,
214	struct mutex *lockblk, unsigned long ip)
215	{
216	printk("\n%s/%d is trying to acquire this lock:\n",
217	current->comm, current->pid);
218	printk_lock(lock, 1);
219	printk("... trying at: ");
220	print_symbol("%s\n", ip);
221	show_held_locks(current);
222
223	if (lockblk) {
224	printk("but %s/%d is deadlocking current task %s/%d!\n\n",
225	task->comm, task->pid, current->comm, current->pid);
226	printk("\n%s/%d is blocked on this lock:\n",
227	task->comm, task->pid);
228	printk_lock(lockblk, 1);
229
230	show_held_locks(task);
231
232	printk("\n%s/%d's [blocked] stackdump:\n\n",
233	task->comm, task->pid);
234	show_stack(task, NULL);
235	}
236
237	printk("\n%s/%d's [current] stackdump:\n\n",
238	current->comm, current->pid);
239	dump_stack();
240	mutex_debug_show_all_locks();
241	printk("[ turning off deadlock detection. Please report this. ]\n\n");
242	local_irq_disable();
243	}
244
245	/*
246	* Recursively check for mutex deadlocks:
247	*/
248	static int check_deadlock(struct mutex *lock, int depth,
249	struct thread_info *ti, unsigned long ip)
250	{
251	struct mutex *lockblk;
252	struct task_struct *task;
253
254	if (!debug_mutex_on)
255	return 0;
256
257	ti = lock->owner;
258	if (!ti)
259	return 0;
260
261	task = ti->task;
262	lockblk = NULL;
263	if (task->blocked_on)
264	lockblk = task->blocked_on->lock;
265
266	/* Self-deadlock: */
267	if (current == task) {
268	DEBUG_OFF();
269	if (depth)
270	return 1;
271	printk("\n==========================================\n");
272	printk( "[ BUG: lock recursion deadlock detected! \|\n");
273	printk( "------------------------------------------\n");
274	report_deadlock(task, lock, NULL, ip);
275	return 0;
276	}
277
278	/* Ugh, something corrupted the lock data structure? */
279	if (depth > 20) {
280	DEBUG_OFF();
281	printk("\n===========================================\n");
282	printk( "[ BUG: infinite lock dependency detected!? \|\n");
283	printk( "-------------------------------------------\n");
284	report_deadlock(task, lock, lockblk, ip);
285	return 0;
286	}
287
288	/* Recursively check for dependencies: */
289	if (lockblk && check_deadlock(lockblk, depth+1, ti, ip)) {
290	printk("\n============================================\n");
291	printk( "[ BUG: circular locking deadlock detected! ]\n");
292	printk( "--------------------------------------------\n");
293	report_deadlock(task, lock, lockblk, ip);
294	return 0;
295	}
296	return 0;
297	}
298
299	/*
300	* Called when a task exits, this function checks whether the
301	* task is holding any locks, and reports the first one if so:
302	*/
303	void mutex_debug_check_no_locks_held(struct task_struct *task)
304	{
305	struct list_head curr, next;
306	struct thread_info *t;
307	unsigned long flags;
308	struct mutex *lock;
309
310	if (!debug_mutex_on)
311	return;
312
313	debug_spin_lock_save(&debug_mutex_lock, flags);
314	list_for_each_safe(curr, next, &debug_mutex_held_locks) {
315	lock = list_entry(curr, struct mutex, held_list);
316	t = lock->owner;
317	if (t != task->thread_info)
318	continue;
319	list_del_init(curr);
320	DEBUG_OFF();
321	debug_spin_lock_restore(&debug_mutex_lock, flags);
322
323	printk("BUG: %s/%d, lock held at task exit time!\n",
324	task->comm, task->pid);
325	printk_lock(lock, 1);
326	if (lock->owner != task->thread_info)
327	printk("exiting task is not even the owner??\n");
328	return;
329	}
330	debug_spin_lock_restore(&debug_mutex_lock, flags);
331	}
332
333	/*
334	* Called when kernel memory is freed (or unmapped), or if a mutex
335	* is destroyed or reinitialized - this code checks whether there is
336	* any held lock in the memory range of <from> to <to>:
337	*/
338	void mutex_debug_check_no_locks_freed(const void from, const void to)
339	{
340	struct list_head curr, next;
341	unsigned long flags;
342	struct mutex *lock;
343	void *lock_addr;
344
345	if (!debug_mutex_on)
346	return;
347
348	debug_spin_lock_save(&debug_mutex_lock, flags);
349	list_for_each_safe(curr, next, &debug_mutex_held_locks) {
350	lock = list_entry(curr, struct mutex, held_list);
351	lock_addr = lock;
352	if (lock_addr < from \|\| lock_addr >= to)
353	continue;
354	list_del_init(curr);
355	DEBUG_OFF();
356	debug_spin_lock_restore(&debug_mutex_lock, flags);
357
358	printk("BUG: %s/%d, active lock [%p(%p-%p)] freed!\n",
359	current->comm, current->pid, lock, from, to);
360	dump_stack();
361	printk_lock(lock, 1);
362	if (lock->owner != current_thread_info())
363	printk("freeing task is not even the owner??\n");
364	return;
365	}
366	debug_spin_lock_restore(&debug_mutex_lock, flags);
367	}
368
369	/*
370	* Must be called with lock->wait_lock held.
371	*/
372	void debug_mutex_set_owner(struct mutex *lock,
373	struct thread_info *new_owner __IP_DECL__)
374	{
375	lock->owner = new_owner;
376	DEBUG_WARN_ON(!list_empty(&lock->held_list));
377	if (debug_mutex_on) {
378	list_add_tail(&lock->held_list, &debug_mutex_held_locks);
379	lock->acquire_ip = ip;
380	}
381	}
382
383	void debug_mutex_init_waiter(struct mutex_waiter *waiter)
384	{
385	memset(waiter, 0x11, sizeof(*waiter));
386	waiter->magic = waiter;
387	INIT_LIST_HEAD(&waiter->list);
388	}
389
390	void debug_mutex_wake_waiter(struct mutex lock, struct mutex_waiter waiter)
391	{
392	SMP_DEBUG_WARN_ON(!spin_is_locked(&lock->wait_lock));
393	DEBUG_WARN_ON(list_empty(&lock->wait_list));
394	DEBUG_WARN_ON(waiter->magic != waiter);
395	DEBUG_WARN_ON(list_empty(&waiter->list));
396	}
397
398	void debug_mutex_free_waiter(struct mutex_waiter *waiter)
399	{
400	DEBUG_WARN_ON(!list_empty(&waiter->list));
401	memset(waiter, 0x22, sizeof(*waiter));
402	}
403
404	void debug_mutex_add_waiter(struct mutex lock, struct mutex_waiter waiter,
405	struct thread_info *ti __IP_DECL__)
406	{
407	SMP_DEBUG_WARN_ON(!spin_is_locked(&lock->wait_lock));
408	check_deadlock(lock, 0, ti, ip);
409	/* Mark the current thread as blocked on the lock: */
410	ti->task->blocked_on = waiter;
411	waiter->lock = lock;
412	}
413
414	void mutex_remove_waiter(struct mutex lock, struct mutex_waiter waiter,
415	struct thread_info *ti)
416	{
417	DEBUG_WARN_ON(list_empty(&waiter->list));
418	DEBUG_WARN_ON(waiter->task != ti->task);
419	DEBUG_WARN_ON(ti->task->blocked_on != waiter);
420	ti->task->blocked_on = NULL;
421
422	list_del_init(&waiter->list);
423	waiter->task = NULL;
424	}
425
426	void debug_mutex_unlock(struct mutex *lock)
427	{
428	DEBUG_WARN_ON(lock->magic != lock);
429	DEBUG_WARN_ON(!lock->wait_list.prev && !lock->wait_list.next);
430	DEBUG_WARN_ON(lock->owner != current_thread_info());
431	if (debug_mutex_on) {
432	DEBUG_WARN_ON(list_empty(&lock->held_list));
433	list_del_init(&lock->held_list);
434	}
435	}
436
437	void debug_mutex_init(struct mutex lock, const char name)
438	{
439	/*
440	* Make sure we are not reinitializing a held lock:
441	*/
442	mutex_debug_check_no_locks_freed((void )lock, (void )(lock + 1));
443	lock->owner = NULL;
444	INIT_LIST_HEAD(&lock->held_list);
445	lock->name = name;
446	lock->magic = lock;
447	}
448
449	/***
450	* mutex_destroy - mark a mutex unusable
451	* @lock: the mutex to be destroyed
452	*
453	* This function marks the mutex uninitialized, and any subsequent
454	* use of the mutex is forbidden. The mutex must not be locked when
455	* this function is called.
456	*/
457	void fastcall mutex_destroy(struct mutex *lock)
458	{
459	DEBUG_WARN_ON(mutex_is_locked(lock));
460	lock->magic = NULL;
461	}
462
463	EXPORT_SYMBOL_GPL(mutex_destroy);
464