[net-next-2.6.git] / kernel / rtmutex-debug.c

/*
 * RT-Mutexes: blocking mutual exclusion locks with PI support
 *
 * started by Ingo Molnar and Thomas Gleixner:
 *
 *  Copyright (C) 2004-2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
 *  Copyright (C) 2006 Timesys Corp., Thomas Gleixner <tglx@timesys.com>
 *
 * This code is based on the rt.c implementation in the preempt-rt tree.
 * Portions of said code are
 *
 *  Copyright (C) 2004  LynuxWorks, Inc., Igor Manyilov, Bill Huey
 *  Copyright (C) 2006  Esben Nielsen
 *  Copyright (C) 2006  Kihon Technologies Inc.,
 *			Steven Rostedt <rostedt@goodmis.org>
 *
 * See rt.c in preempt-rt for proper credits and further information
 */
#include <linux/config.h>
#include <linux/sched.h>
#include <linux/delay.h>
#include <linux/module.h>
#include <linux/spinlock.h>
#include <linux/kallsyms.h>
#include <linux/syscalls.h>
#include <linux/interrupt.h>
#include <linux/plist.h>
#include <linux/fs.h>

#include "rtmutex_common.h"

#ifdef CONFIG_DEBUG_RT_MUTEXES
# include "rtmutex-debug.h"
#else
# include "rtmutex.h"
#endif

# define TRACE_WARN_ON(x)			WARN_ON(x)
# define TRACE_BUG_ON(x)			BUG_ON(x)

# define TRACE_OFF()						\
do {								\
	if (rt_trace_on) {					\
		rt_trace_on = 0;				\
		console_verbose();				\
		if (spin_is_locked(&current->pi_lock))		\
			spin_unlock(&current->pi_lock);		\
		if (spin_is_locked(&current->held_list_lock))	\
			spin_unlock(&current->held_list_lock);	\
	}							\
} while (0)

# define TRACE_OFF_NOLOCK()					\
do {								\
	if (rt_trace_on) {					\
		rt_trace_on = 0;				\
		console_verbose();				\
	}							\
} while (0)

# define TRACE_BUG_LOCKED()			\
do {						\
	TRACE_OFF();				\
	BUG();					\
} while (0)

# define TRACE_WARN_ON_LOCKED(c)		\
do {						\
	if (unlikely(c)) {			\
		TRACE_OFF();			\
		WARN_ON(1);			\
	}					\
} while (0)

# define TRACE_BUG_ON_LOCKED(c)			\
do {						\
	if (unlikely(c))			\
		TRACE_BUG_LOCKED();		\
} while (0)

#ifdef CONFIG_SMP
# define SMP_TRACE_BUG_ON_LOCKED(c)	TRACE_BUG_ON_LOCKED(c)
#else
# define SMP_TRACE_BUG_ON_LOCKED(c)	do { } while (0)
#endif

/*
 * deadlock detection 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 rt_trace_on = 1;

void deadlock_trace_off(void)
{
	rt_trace_on = 0;
}

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

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

static void printk_lock(struct rt_mutex *lock, int print_owner)
{
	if (lock->name)
		printk(" [%p] {%s}\n",
			lock, lock->name);
	else
		printk(" [%p] {%s:%d}\n",
			lock, lock->file, lock->line);

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

static void printk_waiter(struct rt_mutex_waiter *w)
{
	printk("-------------------------\n");
	printk("| waiter struct %p:\n", w);
	printk("| w->list_entry: [DP:%p/%p|SP:%p/%p|PRI:%d]\n",
	       w->list_entry.plist.prio_list.prev, w->list_entry.plist.prio_list.next,
	       w->list_entry.plist.node_list.prev, w->list_entry.plist.node_list.next,
	       w->list_entry.prio);
	printk("| w->pi_list_entry: [DP:%p/%p|SP:%p/%p|PRI:%d]\n",
	       w->pi_list_entry.plist.prio_list.prev, w->pi_list_entry.plist.prio_list.next,
	       w->pi_list_entry.plist.node_list.prev, w->pi_list_entry.plist.node_list.next,
	       w->pi_list_entry.prio);
	printk("\n| lock:\n");
	printk_lock(w->lock, 1);
	printk("| w->ti->task:\n");
	printk_task(w->task);
	printk("| blocked at:  ");
	print_symbol("%s\n", w->ip);
	printk("-------------------------\n");
}

static void show_task_locks(task_t *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->pi_blocked_on) {
		struct rt_mutex *lock = p->pi_blocked_on->lock;

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

void rt_mutex_show_held_locks(task_t *task, int verbose)
{
	struct list_head *curr, *cursor = NULL;
	struct rt_mutex *lock;
	task_t *t;
	unsigned long flags;
	int count = 0;

	if (!rt_trace_on)
		return;

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

next:
	spin_lock_irqsave(&task->held_list_lock, flags);
	list_for_each(curr, &task->held_list_head) {
		if (cursor && curr != cursor)
			continue;
		lock = list_entry(curr, struct rt_mutex, held_list_entry);
		t = rt_mutex_owner(lock);
		WARN_ON(t != task);
		count++;
		cursor = curr->next;
		spin_unlock_irqrestore(&task->held_list_lock, flags);

		printk("\n#%03d:            ", count);
		printk_lock(lock, 0);
		goto next;
	}
	spin_unlock_irqrestore(&task->held_list_lock, flags);

	printk("\n");
}

void rt_mutex_show_all_locks(void)
{
	task_t *g, *p;
	int count = 10;
	int unlock = 1;

	printk("\n");
	printk("----------------------\n");
	printk("| showing all tasks: |\n");
	printk("----------------------\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");

	printk("-----------------------------------------\n");
	printk("| showing all locks held in the system: |\n");
	printk("-----------------------------------------\n");

	do_each_thread(g, p) {
		rt_mutex_show_held_locks(p, 0);
		if (!unlock)
			if (read_trylock(&tasklist_lock))
				unlock = 1;
	} while_each_thread(g, p);


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

	if (unlock)
		read_unlock(&tasklist_lock);
}

void rt_mutex_debug_check_no_locks_held(task_t *task)
{
	struct rt_mutex_waiter *w;
	struct list_head *curr;
	struct rt_mutex *lock;

	if (!rt_trace_on)
		return;
	if (!rt_prio(task->normal_prio) && rt_prio(task->prio)) {
		printk("BUG: PI priority boost leaked!\n");
		printk_task(task);
		printk("\n");
	}
	if (list_empty(&task->held_list_head))
		return;

	spin_lock(&task->pi_lock);
	plist_for_each_entry(w, &task->pi_waiters, pi_list_entry) {
		TRACE_OFF();

		printk("hm, PI interest held at exit time? Task:\n");
		printk_task(task);
		printk_waiter(w);
		return;
	}
	spin_unlock(&task->pi_lock);

	list_for_each(curr, &task->held_list_head) {
		lock = list_entry(curr, struct rt_mutex, held_list_entry);

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

int rt_mutex_debug_check_no_locks_freed(const void *from, unsigned long len)
{
	const void *to = from + len;
	struct list_head *curr;
	struct rt_mutex *lock;
	unsigned long flags;
	void *lock_addr;

	if (!rt_trace_on)
		return 0;

	spin_lock_irqsave(&current->held_list_lock, flags);
	list_for_each(curr, &current->held_list_head) {
		lock = list_entry(curr, struct rt_mutex, held_list_entry);
		lock_addr = lock;
		if (lock_addr < from || lock_addr >= to)
			continue;
		TRACE_OFF();

		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 (rt_mutex_owner(lock) != current)
			printk("freeing task is not even the owner??\n");
		return 1;
	}
	spin_unlock_irqrestore(&current->held_list_lock, flags);

	return 0;
}

void rt_mutex_debug_task_free(struct task_struct *task)
{
	WARN_ON(!plist_head_empty(&task->pi_waiters));
	WARN_ON(task->pi_blocked_on);
}

/*
 * We fill out the fields in the waiter to store the information about
 * the deadlock. We print when we return. act_waiter can be NULL in
 * case of a remove waiter operation.
 */
void debug_rt_mutex_deadlock(int detect, struct rt_mutex_waiter *act_waiter,
			     struct rt_mutex *lock)
{
	struct task_struct *task;

	if (!rt_trace_on || detect || !act_waiter)
		return;

	task = rt_mutex_owner(act_waiter->lock);
	if (task && task != current) {
		act_waiter->deadlock_task_pid = task->pid;
		act_waiter->deadlock_lock = lock;
	}
}

void debug_rt_mutex_print_deadlock(struct rt_mutex_waiter *waiter)
{
	struct task_struct *task;

	if (!waiter->deadlock_lock || !rt_trace_on)
		return;

	task = find_task_by_pid(waiter->deadlock_task_pid);
	if (!task)
		return;

	TRACE_OFF_NOLOCK();

	printk("\n============================================\n");
	printk(  "[ BUG: circular locking deadlock detected! ]\n");
	printk(  "--------------------------------------------\n");
	printk("%s/%d is deadlocking current task %s/%d\n\n",
	       task->comm, task->pid, current->comm, current->pid);

	printk("\n1) %s/%d is trying to acquire this lock:\n",
	       current->comm, current->pid);
	printk_lock(waiter->lock, 1);

	printk("... trying at:                 ");
	print_symbol("%s\n", waiter->ip);

	printk("\n2) %s/%d is blocked on this lock:\n", task->comm, task->pid);
	printk_lock(waiter->deadlock_lock, 1);

	rt_mutex_show_held_locks(current, 1);
	rt_mutex_show_held_locks(task, 1);

	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();
	rt_mutex_show_all_locks();
	printk("[ turning off deadlock detection."
	       "Please report this trace. ]\n\n");
	local_irq_disable();
}

void debug_rt_mutex_lock(struct rt_mutex *lock __IP_DECL__)
{
	unsigned long flags;

	if (rt_trace_on) {
		TRACE_WARN_ON_LOCKED(!list_empty(&lock->held_list_entry));

		spin_lock_irqsave(&current->held_list_lock, flags);
		list_add_tail(&lock->held_list_entry, &current->held_list_head);
		spin_unlock_irqrestore(&current->held_list_lock, flags);

		lock->acquire_ip = ip;
	}
}

void debug_rt_mutex_unlock(struct rt_mutex *lock)
{
	unsigned long flags;

	if (rt_trace_on) {
		TRACE_WARN_ON_LOCKED(rt_mutex_owner(lock) != current);
		TRACE_WARN_ON_LOCKED(list_empty(&lock->held_list_entry));

		spin_lock_irqsave(&current->held_list_lock, flags);
		list_del_init(&lock->held_list_entry);
		spin_unlock_irqrestore(&current->held_list_lock, flags);
	}
}

void debug_rt_mutex_proxy_lock(struct rt_mutex *lock,
			       struct task_struct *powner __IP_DECL__)
{
	unsigned long flags;

	if (rt_trace_on) {
		TRACE_WARN_ON_LOCKED(!list_empty(&lock->held_list_entry));

		spin_lock_irqsave(&powner->held_list_lock, flags);
		list_add_tail(&lock->held_list_entry, &powner->held_list_head);
		spin_unlock_irqrestore(&powner->held_list_lock, flags);

		lock->acquire_ip = ip;
	}
}

void debug_rt_mutex_proxy_unlock(struct rt_mutex *lock)
{
	unsigned long flags;

	if (rt_trace_on) {
		struct task_struct *owner = rt_mutex_owner(lock);

		TRACE_WARN_ON_LOCKED(!owner);
		TRACE_WARN_ON_LOCKED(list_empty(&lock->held_list_entry));

		spin_lock_irqsave(&owner->held_list_lock, flags);
		list_del_init(&lock->held_list_entry);
		spin_unlock_irqrestore(&owner->held_list_lock, flags);
	}
}

void debug_rt_mutex_init_waiter(struct rt_mutex_waiter *waiter)
{
	memset(waiter, 0x11, sizeof(*waiter));
	plist_node_init(&waiter->list_entry, MAX_PRIO);
	plist_node_init(&waiter->pi_list_entry, MAX_PRIO);
}

void debug_rt_mutex_free_waiter(struct rt_mutex_waiter *waiter)
{
	TRACE_WARN_ON(!plist_node_empty(&waiter->list_entry));
	TRACE_WARN_ON(!plist_node_empty(&waiter->pi_list_entry));
	TRACE_WARN_ON(waiter->task);
	memset(waiter, 0x22, sizeof(*waiter));
}

void debug_rt_mutex_init(struct rt_mutex *lock, const char *name)
{
	void *addr = lock;

	if (rt_trace_on) {
		rt_mutex_debug_check_no_locks_freed(addr,
						    sizeof(struct rt_mutex));
		INIT_LIST_HEAD(&lock->held_list_entry);
		lock->name = name;
	}
}

void rt_mutex_deadlock_account_lock(struct rt_mutex *lock, task_t *task)
{
}

void rt_mutex_deadlock_account_unlock(struct task_struct *task)
{
}
Commit	Line	Data
e7eebaf6 IM	1	/*
	2	* RT-Mutexes: blocking mutual exclusion locks with PI support
	3	*
	4	* started by Ingo Molnar and Thomas Gleixner:
	5	*
	6	* Copyright (C) 2004-2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
	7	* Copyright (C) 2006 Timesys Corp., Thomas Gleixner <tglx@timesys.com>
	8	*
	9	* This code is based on the rt.c implementation in the preempt-rt tree.
	10	* Portions of said code are
	11	*
	12	* Copyright (C) 2004 LynuxWorks, Inc., Igor Manyilov, Bill Huey
	13	* Copyright (C) 2006 Esben Nielsen
	14	* Copyright (C) 2006 Kihon Technologies Inc.,
	15	* Steven Rostedt <rostedt@goodmis.org>
	16	*
	17	* See rt.c in preempt-rt for proper credits and further information
	18	*/
	19	#include <linux/config.h>
	20	#include <linux/sched.h>
	21	#include <linux/delay.h>
	22	#include <linux/module.h>
	23	#include <linux/spinlock.h>
	24	#include <linux/kallsyms.h>
	25	#include <linux/syscalls.h>
	26	#include <linux/interrupt.h>
	27	#include <linux/plist.h>
	28	#include <linux/fs.h>
	29
	30	#include "rtmutex_common.h"
	31
	32	#ifdef CONFIG_DEBUG_RT_MUTEXES
	33	# include "rtmutex-debug.h"
	34	#else
	35	# include "rtmutex.h"
	36	#endif
	37
	38	# define TRACE_WARN_ON(x) WARN_ON(x)
	39	# define TRACE_BUG_ON(x) BUG_ON(x)
	40
	41	# define TRACE_OFF() \
	42	do { \
	43	if (rt_trace_on) { \
	44	rt_trace_on = 0; \
	45	console_verbose(); \
	46	if (spin_is_locked(&current->pi_lock)) \
	47	spin_unlock(&current->pi_lock); \
	48	if (spin_is_locked(&current->held_list_lock)) \
	49	spin_unlock(&current->held_list_lock); \
	50	} \
	51	} while (0)
	52
	53	# define TRACE_OFF_NOLOCK() \
	54	do { \
	55	if (rt_trace_on) { \
	56	rt_trace_on = 0; \
	57	console_verbose(); \
	58	} \
	59	} while (0)
	60
	61	# define TRACE_BUG_LOCKED() \
	62	do { \
	63	TRACE_OFF(); \
	64	BUG(); \
65	} while (0)
66
67	# define TRACE_WARN_ON_LOCKED(c) \
68	do { \
69	if (unlikely(c)) { \
70	TRACE_OFF(); \
71	WARN_ON(1); \
72	} \
73	} while (0)
74
75	# define TRACE_BUG_ON_LOCKED(c) \
76	do { \
77	if (unlikely(c)) \
78	TRACE_BUG_LOCKED(); \
79	} while (0)
80
81	#ifdef CONFIG_SMP
82	# define SMP_TRACE_BUG_ON_LOCKED(c) TRACE_BUG_ON_LOCKED(c)
83	#else
84	# define SMP_TRACE_BUG_ON_LOCKED(c) do { } while (0)
85	#endif
86
87	/*
88	* deadlock detection flag. We turn it off when we detect
89	* the first problem because we dont want to recurse back
90	* into the tracing code when doing error printk or
91	* executing a BUG():
92	*/
93	int rt_trace_on = 1;
94
95	void deadlock_trace_off(void)
96	{
97	rt_trace_on = 0;
98	}
99
100	static void printk_task(task_t *p)
101	{
102	if (p)
103	printk("%16s:%5d [%p, %3d]", p->comm, p->pid, p, p->prio);
104	else
105	printk("<none>");
106	}
107
108	static void printk_task_short(task_t *p)
109	{
110	if (p)
111	printk("%s/%d [%p, %3d]", p->comm, p->pid, p, p->prio);
112	else
113	printk("<none>");
114	}
115
116	static void printk_lock(struct rt_mutex *lock, int print_owner)
117	{
118	if (lock->name)
119	printk(" [%p] {%s}\n",
120	lock, lock->name);
121	else
122	printk(" [%p] {%s:%d}\n",
123	lock, lock->file, lock->line);
124
125	if (print_owner && rt_mutex_owner(lock)) {
126	printk(".. ->owner: %p\n", lock->owner);
127	printk(".. held by: ");
128	printk_task(rt_mutex_owner(lock));
129	printk("\n");
130	}
131	if (rt_mutex_owner(lock)) {
132	printk("... acquired at: ");
133	print_symbol("%s\n", lock->acquire_ip);
134	}
135	}
136
137	static void printk_waiter(struct rt_mutex_waiter *w)
138	{
139	printk("-------------------------\n");
140	printk("\| waiter struct %p:\n", w);
141	printk("\| w->list_entry: [DP:%p/%p\|SP:%p/%p\|PRI:%d]\n",
142	w->list_entry.plist.prio_list.prev, w->list_entry.plist.prio_list.next,
143	w->list_entry.plist.node_list.prev, w->list_entry.plist.node_list.next,
144	w->list_entry.prio);
145	printk("\| w->pi_list_entry: [DP:%p/%p\|SP:%p/%p\|PRI:%d]\n",
146	w->pi_list_entry.plist.prio_list.prev, w->pi_list_entry.plist.prio_list.next,
147	w->pi_list_entry.plist.node_list.prev, w->pi_list_entry.plist.node_list.next,
148	w->pi_list_entry.prio);
149	printk("\n\| lock:\n");
150	printk_lock(w->lock, 1);
151	printk("\| w->ti->task:\n");
152	printk_task(w->task);
153	printk("\| blocked at: ");
154	print_symbol("%s\n", w->ip);
155	printk("-------------------------\n");
156	}
157
158	static void show_task_locks(task_t *p)
159	{
160	switch (p->state) {
161	case TASK_RUNNING: printk("R"); break;
162	case TASK_INTERRUPTIBLE: printk("S"); break;
163	case TASK_UNINTERRUPTIBLE: printk("D"); break;
164	case TASK_STOPPED: printk("T"); break;
165	case EXIT_ZOMBIE: printk("Z"); break;
166	case EXIT_DEAD: printk("X"); break;
167	default: printk("?"); break;
168	}
169	printk_task(p);
170	if (p->pi_blocked_on) {
171	struct rt_mutex *lock = p->pi_blocked_on->lock;
172
173	printk(" blocked on:");
174	printk_lock(lock, 1);
175	} else
176	printk(" (not blocked)\n");
177	}
178
179	void rt_mutex_show_held_locks(task_t *task, int verbose)
180	{
181	struct list_head curr, cursor = NULL;
182	struct rt_mutex *lock;
183	task_t *t;
184	unsigned long flags;
185	int count = 0;
186
187	if (!rt_trace_on)
188	return;
189
190	if (verbose) {
191	printk("------------------------------\n");
192	printk("\| showing all locks held by: \| (");
193	printk_task_short(task);
194	printk("):\n");
195	printk("------------------------------\n");
196	}
197
198	next:
199	spin_lock_irqsave(&task->held_list_lock, flags);
200	list_for_each(curr, &task->held_list_head) {
201	if (cursor && curr != cursor)
202	continue;
203	lock = list_entry(curr, struct rt_mutex, held_list_entry);
204	t = rt_mutex_owner(lock);
205	WARN_ON(t != task);
206	count++;
207	cursor = curr->next;
208	spin_unlock_irqrestore(&task->held_list_lock, flags);
209
210	printk("\n#%03d: ", count);
211	printk_lock(lock, 0);
212	goto next;
213	}
214	spin_unlock_irqrestore(&task->held_list_lock, flags);
215
216	printk("\n");
217	}
218
219	void rt_mutex_show_all_locks(void)
220	{
221	task_t g, p;
222	int count = 10;
223	int unlock = 1;
224
225	printk("\n");
226	printk("----------------------\n");
227	printk("\| showing all tasks: \|\n");
228	printk("----------------------\n");
229
230	/*
231	* Here we try to get the tasklist_lock as hard as possible,
232	* if not successful after 2 seconds we ignore it (but keep
233	* trying). This is to enable a debug printout even if a
234	* tasklist_lock-holding task deadlocks or crashes.
235	*/
236	retry:
237	if (!read_trylock(&tasklist_lock)) {
238	if (count == 10)
239	printk("hm, tasklist_lock locked, retrying... ");
240	if (count) {
241	count--;
242	printk(" #%d", 10-count);
243	mdelay(200);
244	goto retry;
245	}
246	printk(" ignoring it.\n");
247	unlock = 0;
248	}
249	if (count != 10)
250	printk(" locked it.\n");
251
252	do_each_thread(g, p) {
253	show_task_locks(p);
254	if (!unlock)
255	if (read_trylock(&tasklist_lock))
256	unlock = 1;
257	} while_each_thread(g, p);
258
259	printk("\n");
260
261	printk("-----------------------------------------\n");
262	printk("\| showing all locks held in the system: \|\n");
263	printk("-----------------------------------------\n");
264
265	do_each_thread(g, p) {
266	rt_mutex_show_held_locks(p, 0);
267	if (!unlock)
268	if (read_trylock(&tasklist_lock))
269	unlock = 1;
270	} while_each_thread(g, p);
271
272
273	printk("=============================================\n\n");
274
275	if (unlock)
276	read_unlock(&tasklist_lock);
277	}
278
279	void rt_mutex_debug_check_no_locks_held(task_t *task)
280	{
281	struct rt_mutex_waiter *w;
282	struct list_head *curr;
283	struct rt_mutex *lock;
284
285	if (!rt_trace_on)
286	return;
287	if (!rt_prio(task->normal_prio) && rt_prio(task->prio)) {
288	printk("BUG: PI priority boost leaked!\n");
289	printk_task(task);
290	printk("\n");
291	}
292	if (list_empty(&task->held_list_head))
293	return;
294
295	spin_lock(&task->pi_lock);
296	plist_for_each_entry(w, &task->pi_waiters, pi_list_entry) {
297	TRACE_OFF();
298
299	printk("hm, PI interest held at exit time? Task:\n");
300	printk_task(task);
301	printk_waiter(w);
302	return;
303	}
304	spin_unlock(&task->pi_lock);
305
306	list_for_each(curr, &task->held_list_head) {
307	lock = list_entry(curr, struct rt_mutex, held_list_entry);
308
309	printk("BUG: %s/%d, lock held at task exit time!\n",
310	task->comm, task->pid);
311	printk_lock(lock, 1);
312	if (rt_mutex_owner(lock) != task)
313	printk("exiting task is not even the owner??\n");
314	}
315	}
316
317	int rt_mutex_debug_check_no_locks_freed(const void *from, unsigned long len)
318	{
319	const void *to = from + len;
320	struct list_head *curr;
321	struct rt_mutex *lock;
322	unsigned long flags;
323	void *lock_addr;
324
325	if (!rt_trace_on)
326	return 0;
327
328	spin_lock_irqsave(&current->held_list_lock, flags);
329	list_for_each(curr, &current->held_list_head) {
330	lock = list_entry(curr, struct rt_mutex, held_list_entry);
331	lock_addr = lock;
332	if (lock_addr < from \|\| lock_addr >= to)
333	continue;
334	TRACE_OFF();
335
336	printk("BUG: %s/%d, active lock [%p(%p-%p)] freed!\n",
337	current->comm, current->pid, lock, from, to);
338	dump_stack();
339	printk_lock(lock, 1);
340	if (rt_mutex_owner(lock) != current)
341	printk("freeing task is not even the owner??\n");
342	return 1;
343	}
344	spin_unlock_irqrestore(&current->held_list_lock, flags);
345
346	return 0;
347	}
348
349	void rt_mutex_debug_task_free(struct task_struct *task)
350	{
351	WARN_ON(!plist_head_empty(&task->pi_waiters));
352	WARN_ON(task->pi_blocked_on);
353	}
354
355	/*
356	* We fill out the fields in the waiter to store the information about
357	* the deadlock. We print when we return. act_waiter can be NULL in
358	* case of a remove waiter operation.
359	*/
360	void debug_rt_mutex_deadlock(int detect, struct rt_mutex_waiter *act_waiter,
361	struct rt_mutex *lock)
362	{
363	struct task_struct *task;
364
365	if (!rt_trace_on \|\| detect \|\| !act_waiter)
366	return;
367
368	task = rt_mutex_owner(act_waiter->lock);
369	if (task && task != current) {
370	act_waiter->deadlock_task_pid = task->pid;
371	act_waiter->deadlock_lock = lock;
372	}
373	}
374
375	void debug_rt_mutex_print_deadlock(struct rt_mutex_waiter *waiter)
376	{
377	struct task_struct *task;
378
379	if (!waiter->deadlock_lock \|\| !rt_trace_on)
380	return;
381
382	task = find_task_by_pid(waiter->deadlock_task_pid);
383	if (!task)
384	return;
385
386	TRACE_OFF_NOLOCK();
387
388	printk("\n============================================\n");
389	printk( "[ BUG: circular locking deadlock detected! ]\n");
390	printk( "--------------------------------------------\n");
391	printk("%s/%d is deadlocking current task %s/%d\n\n",
392	task->comm, task->pid, current->comm, current->pid);
393
394	printk("\n1) %s/%d is trying to acquire this lock:\n",
395	current->comm, current->pid);
396	printk_lock(waiter->lock, 1);
397
398	printk("... trying at: ");
399	print_symbol("%s\n", waiter->ip);
400
401	printk("\n2) %s/%d is blocked on this lock:\n", task->comm, task->pid);
402	printk_lock(waiter->deadlock_lock, 1);
403
404	rt_mutex_show_held_locks(current, 1);
405	rt_mutex_show_held_locks(task, 1);
406
407	printk("\n%s/%d's [blocked] stackdump:\n\n", task->comm, task->pid);
408	show_stack(task, NULL);
409	printk("\n%s/%d's [current] stackdump:\n\n",
410	current->comm, current->pid);
411	dump_stack();
412	rt_mutex_show_all_locks();
413	printk("[ turning off deadlock detection."
414	"Please report this trace. ]\n\n");
415	local_irq_disable();
416	}
417
418	void debug_rt_mutex_lock(struct rt_mutex *lock __IP_DECL__)
419	{
420	unsigned long flags;
421
422	if (rt_trace_on) {
423	TRACE_WARN_ON_LOCKED(!list_empty(&lock->held_list_entry));
424
425	spin_lock_irqsave(&current->held_list_lock, flags);
426	list_add_tail(&lock->held_list_entry, &current->held_list_head);
427	spin_unlock_irqrestore(&current->held_list_lock, flags);
428
429	lock->acquire_ip = ip;
430	}
431	}
432
433	void debug_rt_mutex_unlock(struct rt_mutex *lock)
434	{
435	unsigned long flags;
436
437	if (rt_trace_on) {
438	TRACE_WARN_ON_LOCKED(rt_mutex_owner(lock) != current);
439	TRACE_WARN_ON_LOCKED(list_empty(&lock->held_list_entry));
440
441	spin_lock_irqsave(&current->held_list_lock, flags);
442	list_del_init(&lock->held_list_entry);
443	spin_unlock_irqrestore(&current->held_list_lock, flags);
444	}
445	}
446
447	void debug_rt_mutex_proxy_lock(struct rt_mutex *lock,
448	struct task_struct *powner __IP_DECL__)
449	{
450	unsigned long flags;
451
452	if (rt_trace_on) {
453	TRACE_WARN_ON_LOCKED(!list_empty(&lock->held_list_entry));
454
455	spin_lock_irqsave(&powner->held_list_lock, flags);
456	list_add_tail(&lock->held_list_entry, &powner->held_list_head);
457	spin_unlock_irqrestore(&powner->held_list_lock, flags);
458
459	lock->acquire_ip = ip;
460	}
461	}
462
463	void debug_rt_mutex_proxy_unlock(struct rt_mutex *lock)
464	{
465	unsigned long flags;
466
467	if (rt_trace_on) {
468	struct task_struct *owner = rt_mutex_owner(lock);
469
470	TRACE_WARN_ON_LOCKED(!owner);
471	TRACE_WARN_ON_LOCKED(list_empty(&lock->held_list_entry));
472
473	spin_lock_irqsave(&owner->held_list_lock, flags);
474	list_del_init(&lock->held_list_entry);
475	spin_unlock_irqrestore(&owner->held_list_lock, flags);
476	}
477	}
478
479	void debug_rt_mutex_init_waiter(struct rt_mutex_waiter *waiter)
480	{
481	memset(waiter, 0x11, sizeof(*waiter));
482	plist_node_init(&waiter->list_entry, MAX_PRIO);
483	plist_node_init(&waiter->pi_list_entry, MAX_PRIO);
484	}
485
486	void debug_rt_mutex_free_waiter(struct rt_mutex_waiter *waiter)
487	{
488	TRACE_WARN_ON(!plist_node_empty(&waiter->list_entry));
489	TRACE_WARN_ON(!plist_node_empty(&waiter->pi_list_entry));
490	TRACE_WARN_ON(waiter->task);
491	memset(waiter, 0x22, sizeof(*waiter));
492	}
493
494	void debug_rt_mutex_init(struct rt_mutex lock, const char name)
495	{
496	void *addr = lock;
497
498	if (rt_trace_on) {
499	rt_mutex_debug_check_no_locks_freed(addr,
500	sizeof(struct rt_mutex));
501	INIT_LIST_HEAD(&lock->held_list_entry);
502	lock->name = name;
503	}
504	}
505
506	void rt_mutex_deadlock_account_lock(struct rt_mutex lock, task_t task)
507	{
508	}
509
510	void rt_mutex_deadlock_account_unlock(struct task_struct *task)
511	{
512	}
513