Root/lib/spinlock_debug.c

Source at commit b386be689295730688885552666ea40b2e639b14 created 8 years 11 months ago.
By Maarten ter Huurne, Revert "MIPS: JZ4740: reset: Initialize hibernate wakeup counters."
1/*
2 * Copyright 2005, Red Hat, Inc., Ingo Molnar
3 * Released under the General Public License (GPL).
4 *
5 * This file contains the spinlock/rwlock implementations for
6 * DEBUG_SPINLOCK.
7 */
8
9#include <linux/spinlock.h>
10#include <linux/nmi.h>
11#include <linux/interrupt.h>
12#include <linux/debug_locks.h>
13#include <linux/delay.h>
14#include <linux/module.h>
15
16void __raw_spin_lock_init(raw_spinlock_t *lock, const char *name,
17              struct lock_class_key *key)
18{
19#ifdef CONFIG_DEBUG_LOCK_ALLOC
20    /*
21     * Make sure we are not reinitializing a held lock:
22     */
23    debug_check_no_locks_freed((void *)lock, sizeof(*lock));
24    lockdep_init_map(&lock->dep_map, name, key, 0);
25#endif
26    lock->raw_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
27    lock->magic = SPINLOCK_MAGIC;
28    lock->owner = SPINLOCK_OWNER_INIT;
29    lock->owner_cpu = -1;
30}
31
32EXPORT_SYMBOL(__raw_spin_lock_init);
33
34void __rwlock_init(rwlock_t *lock, const char *name,
35           struct lock_class_key *key)
36{
37#ifdef CONFIG_DEBUG_LOCK_ALLOC
38    /*
39     * Make sure we are not reinitializing a held lock:
40     */
41    debug_check_no_locks_freed((void *)lock, sizeof(*lock));
42    lockdep_init_map(&lock->dep_map, name, key, 0);
43#endif
44    lock->raw_lock = (arch_rwlock_t) __ARCH_RW_LOCK_UNLOCKED;
45    lock->magic = RWLOCK_MAGIC;
46    lock->owner = SPINLOCK_OWNER_INIT;
47    lock->owner_cpu = -1;
48}
49
50EXPORT_SYMBOL(__rwlock_init);
51
52static void spin_dump(raw_spinlock_t *lock, const char *msg)
53{
54    struct task_struct *owner = NULL;
55
56    if (lock->owner && lock->owner != SPINLOCK_OWNER_INIT)
57        owner = lock->owner;
58    printk(KERN_EMERG "BUG: spinlock %s on CPU#%d, %s/%d\n",
59        msg, raw_smp_processor_id(),
60        current->comm, task_pid_nr(current));
61    printk(KERN_EMERG " lock: %p, .magic: %08x, .owner: %s/%d, "
62            ".owner_cpu: %d\n",
63        lock, lock->magic,
64        owner ? owner->comm : "<none>",
65        owner ? task_pid_nr(owner) : -1,
66        lock->owner_cpu);
67    dump_stack();
68}
69
70static void spin_bug(raw_spinlock_t *lock, const char *msg)
71{
72    if (!debug_locks_off())
73        return;
74
75    spin_dump(lock, msg);
76}
77
78#define SPIN_BUG_ON(cond, lock, msg) if (unlikely(cond)) spin_bug(lock, msg)
79
80static inline void
81debug_spin_lock_before(raw_spinlock_t *lock)
82{
83    SPIN_BUG_ON(lock->magic != SPINLOCK_MAGIC, lock, "bad magic");
84    SPIN_BUG_ON(lock->owner == current, lock, "recursion");
85    SPIN_BUG_ON(lock->owner_cpu == raw_smp_processor_id(),
86                            lock, "cpu recursion");
87}
88
89static inline void debug_spin_lock_after(raw_spinlock_t *lock)
90{
91    lock->owner_cpu = raw_smp_processor_id();
92    lock->owner = current;
93}
94
95static inline void debug_spin_unlock(raw_spinlock_t *lock)
96{
97    SPIN_BUG_ON(lock->magic != SPINLOCK_MAGIC, lock, "bad magic");
98    SPIN_BUG_ON(!raw_spin_is_locked(lock), lock, "already unlocked");
99    SPIN_BUG_ON(lock->owner != current, lock, "wrong owner");
100    SPIN_BUG_ON(lock->owner_cpu != raw_smp_processor_id(),
101                            lock, "wrong CPU");
102    lock->owner = SPINLOCK_OWNER_INIT;
103    lock->owner_cpu = -1;
104}
105
106static void __spin_lock_debug(raw_spinlock_t *lock)
107{
108    u64 i;
109    u64 loops = loops_per_jiffy * HZ;
110    int print_once = 1;
111
112    for (;;) {
113        for (i = 0; i < loops; i++) {
114            if (arch_spin_trylock(&lock->raw_lock))
115                return;
116            __delay(1);
117        }
118        /* lockup suspected: */
119        if (print_once) {
120            print_once = 0;
121            spin_dump(lock, "lockup");
122#ifdef CONFIG_SMP
123            trigger_all_cpu_backtrace();
124#endif
125        }
126    }
127}
128
129void do_raw_spin_lock(raw_spinlock_t *lock)
130{
131    debug_spin_lock_before(lock);
132    if (unlikely(!arch_spin_trylock(&lock->raw_lock)))
133        __spin_lock_debug(lock);
134    debug_spin_lock_after(lock);
135}
136
137int do_raw_spin_trylock(raw_spinlock_t *lock)
138{
139    int ret = arch_spin_trylock(&lock->raw_lock);
140
141    if (ret)
142        debug_spin_lock_after(lock);
143#ifndef CONFIG_SMP
144    /*
145     * Must not happen on UP:
146     */
147    SPIN_BUG_ON(!ret, lock, "trylock failure on UP");
148#endif
149    return ret;
150}
151
152void do_raw_spin_unlock(raw_spinlock_t *lock)
153{
154    debug_spin_unlock(lock);
155    arch_spin_unlock(&lock->raw_lock);
156}
157
158static void rwlock_bug(rwlock_t *lock, const char *msg)
159{
160    if (!debug_locks_off())
161        return;
162
163    printk(KERN_EMERG "BUG: rwlock %s on CPU#%d, %s/%d, %p\n",
164        msg, raw_smp_processor_id(), current->comm,
165        task_pid_nr(current), lock);
166    dump_stack();
167}
168
169#define RWLOCK_BUG_ON(cond, lock, msg) if (unlikely(cond)) rwlock_bug(lock, msg)
170
171#if 0 /* __write_lock_debug() can lock up - maybe this can too? */
172static void __read_lock_debug(rwlock_t *lock)
173{
174    u64 i;
175    u64 loops = loops_per_jiffy * HZ;
176    int print_once = 1;
177
178    for (;;) {
179        for (i = 0; i < loops; i++) {
180            if (arch_read_trylock(&lock->raw_lock))
181                return;
182            __delay(1);
183        }
184        /* lockup suspected: */
185        if (print_once) {
186            print_once = 0;
187            printk(KERN_EMERG "BUG: read-lock lockup on CPU#%d, "
188                    "%s/%d, %p\n",
189                raw_smp_processor_id(), current->comm,
190                current->pid, lock);
191            dump_stack();
192        }
193    }
194}
195#endif
196
197void do_raw_read_lock(rwlock_t *lock)
198{
199    RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");
200    arch_read_lock(&lock->raw_lock);
201}
202
203int do_raw_read_trylock(rwlock_t *lock)
204{
205    int ret = arch_read_trylock(&lock->raw_lock);
206
207#ifndef CONFIG_SMP
208    /*
209     * Must not happen on UP:
210     */
211    RWLOCK_BUG_ON(!ret, lock, "trylock failure on UP");
212#endif
213    return ret;
214}
215
216void do_raw_read_unlock(rwlock_t *lock)
217{
218    RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");
219    arch_read_unlock(&lock->raw_lock);
220}
221
222static inline void debug_write_lock_before(rwlock_t *lock)
223{
224    RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");
225    RWLOCK_BUG_ON(lock->owner == current, lock, "recursion");
226    RWLOCK_BUG_ON(lock->owner_cpu == raw_smp_processor_id(),
227                            lock, "cpu recursion");
228}
229
230static inline void debug_write_lock_after(rwlock_t *lock)
231{
232    lock->owner_cpu = raw_smp_processor_id();
233    lock->owner = current;
234}
235
236static inline void debug_write_unlock(rwlock_t *lock)
237{
238    RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");
239    RWLOCK_BUG_ON(lock->owner != current, lock, "wrong owner");
240    RWLOCK_BUG_ON(lock->owner_cpu != raw_smp_processor_id(),
241                            lock, "wrong CPU");
242    lock->owner = SPINLOCK_OWNER_INIT;
243    lock->owner_cpu = -1;
244}
245
246#if 0 /* This can cause lockups */
247static void __write_lock_debug(rwlock_t *lock)
248{
249    u64 i;
250    u64 loops = loops_per_jiffy * HZ;
251    int print_once = 1;
252
253    for (;;) {
254        for (i = 0; i < loops; i++) {
255            if (arch_write_trylock(&lock->raw_lock))
256                return;
257            __delay(1);
258        }
259        /* lockup suspected: */
260        if (print_once) {
261            print_once = 0;
262            printk(KERN_EMERG "BUG: write-lock lockup on CPU#%d, "
263                    "%s/%d, %p\n",
264                raw_smp_processor_id(), current->comm,
265                current->pid, lock);
266            dump_stack();
267        }
268    }
269}
270#endif
271
272void do_raw_write_lock(rwlock_t *lock)
273{
274    debug_write_lock_before(lock);
275    arch_write_lock(&lock->raw_lock);
276    debug_write_lock_after(lock);
277}
278
279int do_raw_write_trylock(rwlock_t *lock)
280{
281    int ret = arch_write_trylock(&lock->raw_lock);
282
283    if (ret)
284        debug_write_lock_after(lock);
285#ifndef CONFIG_SMP
286    /*
287     * Must not happen on UP:
288     */
289    RWLOCK_BUG_ON(!ret, lock, "trylock failure on UP");
290#endif
291    return ret;
292}
293
294void do_raw_write_unlock(rwlock_t *lock)
295{
296    debug_write_unlock(lock);
297    arch_write_unlock(&lock->raw_lock);
298}
299

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