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