1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
|
// SPDX-License-Identifier: GPL-2.0
/*
* 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/sched.h>
#include <linux/sched/rt.h>
#include <linux/sched/debug.h>
#include <linux/delay.h>
#include <linux/export.h>
#include <linux/spinlock.h>
#include <linux/kallsyms.h>
#include <linux/syscalls.h>
#include <linux/interrupt.h>
#include <linux/rbtree.h>
#include <linux/fs.h>
#include <linux/debug_locks.h>
#include "rtmutex_common.h"
static void printk_task(struct task_struct *p)
{
if (p)
printk("%16s:%5d [%p, %3d]", p->comm, task_pid_nr(p), 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");
}
}
void rt_mutex_debug_task_free(struct task_struct *task)
{
DEBUG_LOCKS_WARN_ON(!RB_EMPTY_ROOT(&task->pi_waiters.rb_root));
DEBUG_LOCKS_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(enum rtmutex_chainwalk chwalk,
struct rt_mutex_waiter *act_waiter,
struct rt_mutex *lock)
{
struct task_struct *task;
if (!debug_locks || chwalk == RT_MUTEX_FULL_CHAINWALK || !act_waiter)
return;
task = rt_mutex_owner(act_waiter->lock);
if (task && task != current) {
act_waiter->deadlock_task_pid = get_pid(task_pid(task));
act_waiter->deadlock_lock = lock;
}
}
void debug_rt_mutex_print_deadlock(struct rt_mutex_waiter *waiter)
{
struct task_struct *task;
if (!waiter->deadlock_lock || !debug_locks)
return;
rcu_read_lock();
task = pid_task(waiter->deadlock_task_pid, PIDTYPE_PID);
if (!task) {
rcu_read_unlock();
return;
}
if (!debug_locks_off()) {
rcu_read_unlock();
return;
}
pr_warn("\n");
pr_warn("============================================\n");
pr_warn("WARNING: circular locking deadlock detected!\n");
pr_warn("%s\n", print_tainted());
pr_warn("--------------------------------------------\n");
printk("%s/%d is deadlocking current task %s/%d\n\n",
task->comm, task_pid_nr(task),
current->comm, task_pid_nr(current));
printk("\n1) %s/%d is trying to acquire this lock:\n",
current->comm, task_pid_nr(current));
printk_lock(waiter->lock, 1);
printk("\n2) %s/%d is blocked on this lock:\n",
task->comm, task_pid_nr(task));
printk_lock(waiter->deadlock_lock, 1);
debug_show_held_locks(current);
debug_show_held_locks(task);
printk("\n%s/%d's [blocked] stackdump:\n\n",
task->comm, task_pid_nr(task));
show_stack(task, NULL);
printk("\n%s/%d's [current] stackdump:\n\n",
current->comm, task_pid_nr(current));
dump_stack();
debug_show_all_locks();
rcu_read_unlock();
printk("[ turning off deadlock detection."
"Please report this trace. ]\n\n");
}
void debug_rt_mutex_lock(struct rt_mutex *lock)
{
}
void debug_rt_mutex_unlock(struct rt_mutex *lock)
{
DEBUG_LOCKS_WARN_ON(rt_mutex_owner(lock) != current);
}
void
debug_rt_mutex_proxy_lock(struct rt_mutex *lock, struct task_struct *powner)
{
}
void debug_rt_mutex_proxy_unlock(struct rt_mutex *lock)
{
DEBUG_LOCKS_WARN_ON(!rt_mutex_owner(lock));
}
void debug_rt_mutex_init_waiter(struct rt_mutex_waiter *waiter)
{
memset(waiter, 0x11, sizeof(*waiter));
waiter->deadlock_task_pid = NULL;
}
void debug_rt_mutex_free_waiter(struct rt_mutex_waiter *waiter)
{
put_pid(waiter->deadlock_task_pid);
memset(waiter, 0x22, sizeof(*waiter));
}
void debug_rt_mutex_init(struct rt_mutex *lock, const char *name, struct lock_class_key *key)
{
/*
* Make sure we are not reinitializing a held lock:
*/
debug_check_no_locks_freed((void *)lock, sizeof(*lock));
lock->name = name;
#ifdef CONFIG_DEBUG_LOCK_ALLOC
lockdep_init_map(&lock->dep_map, name, key, 0);
#endif
}
|
