Driver core: add CONFIG_UEVENT_HELPER_PATH
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / kernel / rtmutex-debug.c
blob5aedbee014dfca7f2ebdce84e62d1c1bac87fab2
1 /*
2 * RT-Mutexes: blocking mutual exclusion locks with PI support
4 * started by Ingo Molnar and Thomas Gleixner:
6 * Copyright (C) 2004-2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
7 * Copyright (C) 2006 Timesys Corp., Thomas Gleixner <tglx@timesys.com>
9 * This code is based on the rt.c implementation in the preempt-rt tree.
10 * Portions of said code are
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>
17 * See rt.c in preempt-rt for proper credits and further information
19 #include <linux/sched.h>
20 #include <linux/delay.h>
21 #include <linux/module.h>
22 #include <linux/spinlock.h>
23 #include <linux/kallsyms.h>
24 #include <linux/syscalls.h>
25 #include <linux/interrupt.h>
26 #include <linux/plist.h>
27 #include <linux/fs.h>
28 #include <linux/debug_locks.h>
30 #include "rtmutex_common.h"
32 # define TRACE_WARN_ON(x) WARN_ON(x)
33 # define TRACE_BUG_ON(x) BUG_ON(x)
35 # define TRACE_OFF() \
36 do { \
37 if (rt_trace_on) { \
38 rt_trace_on = 0; \
39 console_verbose(); \
40 if (spin_is_locked(&current->pi_lock)) \
41 spin_unlock(&current->pi_lock); \
42 } \
43 } while (0)
45 # define TRACE_OFF_NOLOCK() \
46 do { \
47 if (rt_trace_on) { \
48 rt_trace_on = 0; \
49 console_verbose(); \
50 } \
51 } while (0)
53 # define TRACE_BUG_LOCKED() \
54 do { \
55 TRACE_OFF(); \
56 BUG(); \
57 } while (0)
59 # define TRACE_WARN_ON_LOCKED(c) \
60 do { \
61 if (unlikely(c)) { \
62 TRACE_OFF(); \
63 WARN_ON(1); \
64 } \
65 } while (0)
67 # define TRACE_BUG_ON_LOCKED(c) \
68 do { \
69 if (unlikely(c)) \
70 TRACE_BUG_LOCKED(); \
71 } while (0)
73 #ifdef CONFIG_SMP
74 # define SMP_TRACE_BUG_ON_LOCKED(c) TRACE_BUG_ON_LOCKED(c)
75 #else
76 # define SMP_TRACE_BUG_ON_LOCKED(c) do { } while (0)
77 #endif
80 * deadlock detection flag. We turn it off when we detect
81 * the first problem because we dont want to recurse back
82 * into the tracing code when doing error printk or
83 * executing a BUG():
85 int rt_trace_on = 1;
87 void deadlock_trace_off(void)
89 rt_trace_on = 0;
92 static void printk_task(struct task_struct *p)
94 if (p)
95 printk("%16s:%5d [%p, %3d]", p->comm, p->pid, p, p->prio);
96 else
97 printk("<none>");
100 static void printk_lock(struct rt_mutex *lock, int print_owner)
102 if (lock->name)
103 printk(" [%p] {%s}\n",
104 lock, lock->name);
105 else
106 printk(" [%p] {%s:%d}\n",
107 lock, lock->file, lock->line);
109 if (print_owner && rt_mutex_owner(lock)) {
110 printk(".. ->owner: %p\n", lock->owner);
111 printk(".. held by: ");
112 printk_task(rt_mutex_owner(lock));
113 printk("\n");
117 void rt_mutex_debug_task_free(struct task_struct *task)
119 WARN_ON(!plist_head_empty(&task->pi_waiters));
120 WARN_ON(task->pi_blocked_on);
124 * We fill out the fields in the waiter to store the information about
125 * the deadlock. We print when we return. act_waiter can be NULL in
126 * case of a remove waiter operation.
128 void debug_rt_mutex_deadlock(int detect, struct rt_mutex_waiter *act_waiter,
129 struct rt_mutex *lock)
131 struct task_struct *task;
133 if (!rt_trace_on || detect || !act_waiter)
134 return;
136 task = rt_mutex_owner(act_waiter->lock);
137 if (task && task != current) {
138 act_waiter->deadlock_task_pid = task->pid;
139 act_waiter->deadlock_lock = lock;
143 void debug_rt_mutex_print_deadlock(struct rt_mutex_waiter *waiter)
145 struct task_struct *task;
147 if (!waiter->deadlock_lock || !rt_trace_on)
148 return;
150 task = find_task_by_pid(waiter->deadlock_task_pid);
151 if (!task)
152 return;
154 TRACE_OFF_NOLOCK();
156 printk("\n============================================\n");
157 printk( "[ BUG: circular locking deadlock detected! ]\n");
158 printk( "--------------------------------------------\n");
159 printk("%s/%d is deadlocking current task %s/%d\n\n",
160 task->comm, task->pid, current->comm, current->pid);
162 printk("\n1) %s/%d is trying to acquire this lock:\n",
163 current->comm, current->pid);
164 printk_lock(waiter->lock, 1);
166 printk("\n2) %s/%d is blocked on this lock:\n", task->comm, task->pid);
167 printk_lock(waiter->deadlock_lock, 1);
169 debug_show_held_locks(current);
170 debug_show_held_locks(task);
172 printk("\n%s/%d's [blocked] stackdump:\n\n", task->comm, task->pid);
173 show_stack(task, NULL);
174 printk("\n%s/%d's [current] stackdump:\n\n",
175 current->comm, current->pid);
176 dump_stack();
177 debug_show_all_locks();
179 printk("[ turning off deadlock detection."
180 "Please report this trace. ]\n\n");
181 local_irq_disable();
184 void debug_rt_mutex_lock(struct rt_mutex *lock)
188 void debug_rt_mutex_unlock(struct rt_mutex *lock)
190 TRACE_WARN_ON_LOCKED(rt_mutex_owner(lock) != current);
193 void
194 debug_rt_mutex_proxy_lock(struct rt_mutex *lock, struct task_struct *powner)
198 void debug_rt_mutex_proxy_unlock(struct rt_mutex *lock)
200 TRACE_WARN_ON_LOCKED(!rt_mutex_owner(lock));
203 void debug_rt_mutex_init_waiter(struct rt_mutex_waiter *waiter)
205 memset(waiter, 0x11, sizeof(*waiter));
206 plist_node_init(&waiter->list_entry, MAX_PRIO);
207 plist_node_init(&waiter->pi_list_entry, MAX_PRIO);
210 void debug_rt_mutex_free_waiter(struct rt_mutex_waiter *waiter)
212 TRACE_WARN_ON(!plist_node_empty(&waiter->list_entry));
213 TRACE_WARN_ON(!plist_node_empty(&waiter->pi_list_entry));
214 TRACE_WARN_ON(waiter->task);
215 memset(waiter, 0x22, sizeof(*waiter));
218 void debug_rt_mutex_init(struct rt_mutex *lock, const char *name)
221 * Make sure we are not reinitializing a held lock:
223 debug_check_no_locks_freed((void *)lock, sizeof(*lock));
224 lock->name = name;
227 void
228 rt_mutex_deadlock_account_lock(struct rt_mutex *lock, struct task_struct *task)
232 void rt_mutex_deadlock_account_unlock(struct task_struct *task)