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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
e7eebaf6 IM |
2 | /* |
3 | * RT-Mutexes: blocking mutual exclusion locks with PI support | |
4 | * | |
5 | * started by Ingo Molnar and Thomas Gleixner: | |
6 | * | |
7 | * Copyright (C) 2004-2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com> | |
8 | * Copyright (C) 2006 Timesys Corp., Thomas Gleixner <tglx@timesys.com> | |
9 | * | |
10 | * This code is based on the rt.c implementation in the preempt-rt tree. | |
11 | * Portions of said code are | |
12 | * | |
13 | * Copyright (C) 2004 LynuxWorks, Inc., Igor Manyilov, Bill Huey | |
14 | * Copyright (C) 2006 Esben Nielsen | |
15 | * Copyright (C) 2006 Kihon Technologies Inc., | |
16 | * Steven Rostedt <rostedt@goodmis.org> | |
17 | * | |
18 | * See rt.c in preempt-rt for proper credits and further information | |
19 | */ | |
e7eebaf6 | 20 | #include <linux/sched.h> |
8bd75c77 | 21 | #include <linux/sched/rt.h> |
b17b0153 | 22 | #include <linux/sched/debug.h> |
e7eebaf6 | 23 | #include <linux/delay.h> |
9984de1a | 24 | #include <linux/export.h> |
e7eebaf6 IM |
25 | #include <linux/spinlock.h> |
26 | #include <linux/kallsyms.h> | |
27 | #include <linux/syscalls.h> | |
28 | #include <linux/interrupt.h> | |
fb00aca4 | 29 | #include <linux/rbtree.h> |
e7eebaf6 | 30 | #include <linux/fs.h> |
9a11b49a | 31 | #include <linux/debug_locks.h> |
e7eebaf6 IM |
32 | |
33 | #include "rtmutex_common.h" | |
34 | ||
36c8b586 | 35 | static void printk_task(struct task_struct *p) |
e7eebaf6 IM |
36 | { |
37 | if (p) | |
ba25f9dc | 38 | printk("%16s:%5d [%p, %3d]", p->comm, task_pid_nr(p), p, p->prio); |
e7eebaf6 IM |
39 | else |
40 | printk("<none>"); | |
41 | } | |
42 | ||
e7eebaf6 IM |
43 | static void printk_lock(struct rt_mutex *lock, int print_owner) |
44 | { | |
45 | if (lock->name) | |
46 | printk(" [%p] {%s}\n", | |
47 | lock, lock->name); | |
48 | else | |
49 | printk(" [%p] {%s:%d}\n", | |
50 | lock, lock->file, lock->line); | |
51 | ||
52 | if (print_owner && rt_mutex_owner(lock)) { | |
53 | printk(".. ->owner: %p\n", lock->owner); | |
54 | printk(".. held by: "); | |
55 | printk_task(rt_mutex_owner(lock)); | |
56 | printk("\n"); | |
57 | } | |
e7eebaf6 IM |
58 | } |
59 | ||
60 | void rt_mutex_debug_task_free(struct task_struct *task) | |
61 | { | |
a23ba907 | 62 | DEBUG_LOCKS_WARN_ON(!RB_EMPTY_ROOT(&task->pi_waiters.rb_root)); |
0fa914c6 | 63 | DEBUG_LOCKS_WARN_ON(task->pi_blocked_on); |
e7eebaf6 IM |
64 | } |
65 | ||
66 | /* | |
67 | * We fill out the fields in the waiter to store the information about | |
68 | * the deadlock. We print when we return. act_waiter can be NULL in | |
69 | * case of a remove waiter operation. | |
70 | */ | |
8930ed80 TG |
71 | void debug_rt_mutex_deadlock(enum rtmutex_chainwalk chwalk, |
72 | struct rt_mutex_waiter *act_waiter, | |
e7eebaf6 IM |
73 | struct rt_mutex *lock) |
74 | { | |
75 | struct task_struct *task; | |
76 | ||
8930ed80 | 77 | if (!debug_locks || chwalk == RT_MUTEX_FULL_CHAINWALK || !act_waiter) |
e7eebaf6 IM |
78 | return; |
79 | ||
80 | task = rt_mutex_owner(act_waiter->lock); | |
81 | if (task && task != current) { | |
48d13e48 | 82 | act_waiter->deadlock_task_pid = get_pid(task_pid(task)); |
e7eebaf6 IM |
83 | act_waiter->deadlock_lock = lock; |
84 | } | |
85 | } | |
86 | ||
87 | void debug_rt_mutex_print_deadlock(struct rt_mutex_waiter *waiter) | |
88 | { | |
89 | struct task_struct *task; | |
90 | ||
0fa914c6 | 91 | if (!waiter->deadlock_lock || !debug_locks) |
e7eebaf6 IM |
92 | return; |
93 | ||
48d13e48 PE |
94 | rcu_read_lock(); |
95 | task = pid_task(waiter->deadlock_task_pid, PIDTYPE_PID); | |
96 | if (!task) { | |
97 | rcu_read_unlock(); | |
e7eebaf6 | 98 | return; |
48d13e48 | 99 | } |
e7eebaf6 | 100 | |
68cc3990 TG |
101 | if (!debug_locks_off()) { |
102 | rcu_read_unlock(); | |
0fa914c6 | 103 | return; |
68cc3990 | 104 | } |
e7eebaf6 | 105 | |
a5dd63ef PM |
106 | pr_warn("\n"); |
107 | pr_warn("============================================\n"); | |
108 | pr_warn("WARNING: circular locking deadlock detected!\n"); | |
109 | pr_warn("%s\n", print_tainted()); | |
110 | pr_warn("--------------------------------------------\n"); | |
e7eebaf6 | 111 | printk("%s/%d is deadlocking current task %s/%d\n\n", |
ba25f9dc PE |
112 | task->comm, task_pid_nr(task), |
113 | current->comm, task_pid_nr(current)); | |
e7eebaf6 IM |
114 | |
115 | printk("\n1) %s/%d is trying to acquire this lock:\n", | |
ba25f9dc | 116 | current->comm, task_pid_nr(current)); |
e7eebaf6 IM |
117 | printk_lock(waiter->lock, 1); |
118 | ||
ba25f9dc PE |
119 | printk("\n2) %s/%d is blocked on this lock:\n", |
120 | task->comm, task_pid_nr(task)); | |
e7eebaf6 IM |
121 | printk_lock(waiter->deadlock_lock, 1); |
122 | ||
9a11b49a IM |
123 | debug_show_held_locks(current); |
124 | debug_show_held_locks(task); | |
e7eebaf6 | 125 | |
ba25f9dc PE |
126 | printk("\n%s/%d's [blocked] stackdump:\n\n", |
127 | task->comm, task_pid_nr(task)); | |
e7eebaf6 IM |
128 | show_stack(task, NULL); |
129 | printk("\n%s/%d's [current] stackdump:\n\n", | |
ba25f9dc | 130 | current->comm, task_pid_nr(current)); |
e7eebaf6 | 131 | dump_stack(); |
9a11b49a | 132 | debug_show_all_locks(); |
48d13e48 | 133 | rcu_read_unlock(); |
9a11b49a | 134 | |
e7eebaf6 IM |
135 | printk("[ turning off deadlock detection." |
136 | "Please report this trace. ]\n\n"); | |
e7eebaf6 IM |
137 | } |
138 | ||
9a11b49a | 139 | void debug_rt_mutex_lock(struct rt_mutex *lock) |
e7eebaf6 | 140 | { |
e7eebaf6 IM |
141 | } |
142 | ||
143 | void debug_rt_mutex_unlock(struct rt_mutex *lock) | |
144 | { | |
0fa914c6 | 145 | DEBUG_LOCKS_WARN_ON(rt_mutex_owner(lock) != current); |
e7eebaf6 IM |
146 | } |
147 | ||
9a11b49a IM |
148 | void |
149 | debug_rt_mutex_proxy_lock(struct rt_mutex *lock, struct task_struct *powner) | |
e7eebaf6 | 150 | { |
e7eebaf6 IM |
151 | } |
152 | ||
153 | void debug_rt_mutex_proxy_unlock(struct rt_mutex *lock) | |
154 | { | |
0fa914c6 | 155 | DEBUG_LOCKS_WARN_ON(!rt_mutex_owner(lock)); |
e7eebaf6 IM |
156 | } |
157 | ||
158 | void debug_rt_mutex_init_waiter(struct rt_mutex_waiter *waiter) | |
159 | { | |
160 | memset(waiter, 0x11, sizeof(*waiter)); | |
48d13e48 | 161 | waiter->deadlock_task_pid = NULL; |
e7eebaf6 IM |
162 | } |
163 | ||
164 | void debug_rt_mutex_free_waiter(struct rt_mutex_waiter *waiter) | |
165 | { | |
48d13e48 | 166 | put_pid(waiter->deadlock_task_pid); |
e7eebaf6 IM |
167 | memset(waiter, 0x22, sizeof(*waiter)); |
168 | } | |
169 | ||
f5694788 | 170 | void debug_rt_mutex_init(struct rt_mutex *lock, const char *name, struct lock_class_key *key) |
e7eebaf6 | 171 | { |
9a11b49a IM |
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; | |
f5694788 PZ |
177 | |
178 | #ifdef CONFIG_DEBUG_LOCK_ALLOC | |
179 | lockdep_init_map(&lock->dep_map, name, key, 0); | |
180 | #endif | |
e7eebaf6 IM |
181 | } |
182 |