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Source at commit b13e7eb172b6f08e5fc22da162bdde5fcde201b5 created 11 years 11 months ago. By Maarten ter Huurne, fbcon: Add 6x10 font | |
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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/sched.h> |
20 | #include <linux/delay.h> |
21 | #include <linux/export.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> |
29 | |
30 | #include "rtmutex_common.h" |
31 | |
32 | static void printk_task(struct task_struct *p) |
33 | { |
34 | if (p) |
35 | printk("%16s:%5d [%p, %3d]", p->comm, task_pid_nr(p), p, p->prio); |
36 | else |
37 | printk("<none>"); |
38 | } |
39 | |
40 | static void printk_lock(struct rt_mutex *lock, int print_owner) |
41 | { |
42 | if (lock->name) |
43 | printk(" [%p] {%s}\n", |
44 | lock, lock->name); |
45 | else |
46 | printk(" [%p] {%s:%d}\n", |
47 | lock, lock->file, lock->line); |
48 | |
49 | if (print_owner && rt_mutex_owner(lock)) { |
50 | printk(".. ->owner: %p\n", lock->owner); |
51 | printk(".. held by: "); |
52 | printk_task(rt_mutex_owner(lock)); |
53 | printk("\n"); |
54 | } |
55 | } |
56 | |
57 | void rt_mutex_debug_task_free(struct task_struct *task) |
58 | { |
59 | DEBUG_LOCKS_WARN_ON(!plist_head_empty(&task->pi_waiters)); |
60 | DEBUG_LOCKS_WARN_ON(task->pi_blocked_on); |
61 | } |
62 | |
63 | /* |
64 | * We fill out the fields in the waiter to store the information about |
65 | * the deadlock. We print when we return. act_waiter can be NULL in |
66 | * case of a remove waiter operation. |
67 | */ |
68 | void debug_rt_mutex_deadlock(int detect, struct rt_mutex_waiter *act_waiter, |
69 | struct rt_mutex *lock) |
70 | { |
71 | struct task_struct *task; |
72 | |
73 | if (!debug_locks || detect || !act_waiter) |
74 | return; |
75 | |
76 | task = rt_mutex_owner(act_waiter->lock); |
77 | if (task && task != current) { |
78 | act_waiter->deadlock_task_pid = get_pid(task_pid(task)); |
79 | act_waiter->deadlock_lock = lock; |
80 | } |
81 | } |
82 | |
83 | void debug_rt_mutex_print_deadlock(struct rt_mutex_waiter *waiter) |
84 | { |
85 | struct task_struct *task; |
86 | |
87 | if (!waiter->deadlock_lock || !debug_locks) |
88 | return; |
89 | |
90 | rcu_read_lock(); |
91 | task = pid_task(waiter->deadlock_task_pid, PIDTYPE_PID); |
92 | if (!task) { |
93 | rcu_read_unlock(); |
94 | return; |
95 | } |
96 | |
97 | if (!debug_locks_off()) { |
98 | rcu_read_unlock(); |
99 | return; |
100 | } |
101 | |
102 | printk("\n============================================\n"); |
103 | printk( "[ BUG: circular locking deadlock detected! ]\n"); |
104 | printk("%s\n", print_tainted()); |
105 | printk( "--------------------------------------------\n"); |
106 | printk("%s/%d is deadlocking current task %s/%d\n\n", |
107 | task->comm, task_pid_nr(task), |
108 | current->comm, task_pid_nr(current)); |
109 | |
110 | printk("\n1) %s/%d is trying to acquire this lock:\n", |
111 | current->comm, task_pid_nr(current)); |
112 | printk_lock(waiter->lock, 1); |
113 | |
114 | printk("\n2) %s/%d is blocked on this lock:\n", |
115 | task->comm, task_pid_nr(task)); |
116 | printk_lock(waiter->deadlock_lock, 1); |
117 | |
118 | debug_show_held_locks(current); |
119 | debug_show_held_locks(task); |
120 | |
121 | printk("\n%s/%d's [blocked] stackdump:\n\n", |
122 | task->comm, task_pid_nr(task)); |
123 | show_stack(task, NULL); |
124 | printk("\n%s/%d's [current] stackdump:\n\n", |
125 | current->comm, task_pid_nr(current)); |
126 | dump_stack(); |
127 | debug_show_all_locks(); |
128 | rcu_read_unlock(); |
129 | |
130 | printk("[ turning off deadlock detection." |
131 | "Please report this trace. ]\n\n"); |
132 | } |
133 | |
134 | void debug_rt_mutex_lock(struct rt_mutex *lock) |
135 | { |
136 | } |
137 | |
138 | void debug_rt_mutex_unlock(struct rt_mutex *lock) |
139 | { |
140 | DEBUG_LOCKS_WARN_ON(rt_mutex_owner(lock) != current); |
141 | } |
142 | |
143 | void |
144 | debug_rt_mutex_proxy_lock(struct rt_mutex *lock, struct task_struct *powner) |
145 | { |
146 | } |
147 | |
148 | void debug_rt_mutex_proxy_unlock(struct rt_mutex *lock) |
149 | { |
150 | DEBUG_LOCKS_WARN_ON(!rt_mutex_owner(lock)); |
151 | } |
152 | |
153 | void debug_rt_mutex_init_waiter(struct rt_mutex_waiter *waiter) |
154 | { |
155 | memset(waiter, 0x11, sizeof(*waiter)); |
156 | plist_node_init(&waiter->list_entry, MAX_PRIO); |
157 | plist_node_init(&waiter->pi_list_entry, MAX_PRIO); |
158 | waiter->deadlock_task_pid = NULL; |
159 | } |
160 | |
161 | void debug_rt_mutex_free_waiter(struct rt_mutex_waiter *waiter) |
162 | { |
163 | put_pid(waiter->deadlock_task_pid); |
164 | DEBUG_LOCKS_WARN_ON(!plist_node_empty(&waiter->list_entry)); |
165 | DEBUG_LOCKS_WARN_ON(!plist_node_empty(&waiter->pi_list_entry)); |
166 | memset(waiter, 0x22, sizeof(*waiter)); |
167 | } |
168 | |
169 | void debug_rt_mutex_init(struct rt_mutex *lock, const char *name) |
170 | { |
171 | /* |
172 | * Make sure we are not reinitializing a held lock: |
173 | */ |
174 | debug_check_no_locks_freed((void *)lock, sizeof(*lock)); |
175 | lock->name = name; |
176 | } |
177 | |
178 | void |
179 | rt_mutex_deadlock_account_lock(struct rt_mutex *lock, struct task_struct *task) |
180 | { |
181 | } |
182 | |
183 | void rt_mutex_deadlock_account_unlock(struct task_struct *task) |
184 | { |
185 | } |
186 | |
187 |
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