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-rw-r--r--lib/Makefile2
-rw-r--r--lib/debug_locks.c45
-rw-r--r--lib/spinlock_debug.c62
3 files changed, 72 insertions, 37 deletions
diff --git a/lib/Makefile b/lib/Makefile
index 10c13c9d7824..4f5d01922f82 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -11,7 +11,7 @@ lib-$(CONFIG_SMP) += cpumask.o
11 11
12lib-y += kobject.o kref.o kobject_uevent.o klist.o 12lib-y += kobject.o kref.o kobject_uevent.o klist.o
13 13
14obj-y += sort.o parser.o halfmd4.o iomap_copy.o 14obj-y += sort.o parser.o halfmd4.o iomap_copy.o debug_locks.o
15 15
16ifeq ($(CONFIG_DEBUG_KOBJECT),y) 16ifeq ($(CONFIG_DEBUG_KOBJECT),y)
17CFLAGS_kobject.o += -DDEBUG 17CFLAGS_kobject.o += -DDEBUG
diff --git a/lib/debug_locks.c b/lib/debug_locks.c
new file mode 100644
index 000000000000..0ef01d14727c
--- /dev/null
+++ b/lib/debug_locks.c
@@ -0,0 +1,45 @@
1/*
2 * lib/debug_locks.c
3 *
4 * Generic place for common debugging facilities for various locks:
5 * spinlocks, rwlocks, mutexes and rwsems.
6 *
7 * Started by Ingo Molnar:
8 *
9 * Copyright (C) 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
10 */
11#include <linux/rwsem.h>
12#include <linux/mutex.h>
13#include <linux/module.h>
14#include <linux/spinlock.h>
15#include <linux/debug_locks.h>
16
17/*
18 * We want to turn all lock-debugging facilities on/off at once,
19 * via a global flag. The reason is that once a single bug has been
20 * detected and reported, there might be cascade of followup bugs
21 * that would just muddy the log. So we report the first one and
22 * shut up after that.
23 */
24int debug_locks = 1;
25
26/*
27 * The locking-testsuite uses <debug_locks_silent> to get a
28 * 'silent failure': nothing is printed to the console when
29 * a locking bug is detected.
30 */
31int debug_locks_silent;
32
33/*
34 * Generic 'turn off all lock debugging' function:
35 */
36int debug_locks_off(void)
37{
38 if (xchg(&debug_locks, 0)) {
39 if (!debug_locks_silent) {
40 console_verbose();
41 return 1;
42 }
43 }
44 return 0;
45}
diff --git a/lib/spinlock_debug.c b/lib/spinlock_debug.c
index 93c15ee3f8ea..3de2ccf48ac6 100644
--- a/lib/spinlock_debug.c
+++ b/lib/spinlock_debug.c
@@ -8,38 +8,35 @@
8 8
9#include <linux/spinlock.h> 9#include <linux/spinlock.h>
10#include <linux/interrupt.h> 10#include <linux/interrupt.h>
11#include <linux/debug_locks.h>
11#include <linux/delay.h> 12#include <linux/delay.h>
13#include <linux/module.h>
12 14
13static void spin_bug(spinlock_t *lock, const char *msg) 15static void spin_bug(spinlock_t *lock, const char *msg)
14{ 16{
15 static long print_once = 1;
16 struct task_struct *owner = NULL; 17 struct task_struct *owner = NULL;
17 18
18 if (xchg(&print_once, 0)) { 19 if (!debug_locks_off())
19 if (lock->owner && lock->owner != SPINLOCK_OWNER_INIT) 20 return;
20 owner = lock->owner; 21
21 printk(KERN_EMERG "BUG: spinlock %s on CPU#%d, %s/%d\n", 22 if (lock->owner && lock->owner != SPINLOCK_OWNER_INIT)
22 msg, raw_smp_processor_id(), 23 owner = lock->owner;
23 current->comm, current->pid); 24 printk(KERN_EMERG "BUG: spinlock %s on CPU#%d, %s/%d\n",
24 printk(KERN_EMERG " lock: %p, .magic: %08x, .owner: %s/%d, " 25 msg, raw_smp_processor_id(),
25 ".owner_cpu: %d\n", 26 current->comm, current->pid);
26 lock, lock->magic, 27 printk(KERN_EMERG " lock: %p, .magic: %08x, .owner: %s/%d, "
27 owner ? owner->comm : "<none>", 28 ".owner_cpu: %d\n",
28 owner ? owner->pid : -1, 29 lock, lock->magic,
29 lock->owner_cpu); 30 owner ? owner->comm : "<none>",
30 dump_stack(); 31 owner ? owner->pid : -1,
31#ifdef CONFIG_SMP 32 lock->owner_cpu);
32 /* 33 dump_stack();
33 * We cannot continue on SMP:
34 */
35// panic("bad locking");
36#endif
37 }
38} 34}
39 35
40#define SPIN_BUG_ON(cond, lock, msg) if (unlikely(cond)) spin_bug(lock, msg) 36#define SPIN_BUG_ON(cond, lock, msg) if (unlikely(cond)) spin_bug(lock, msg)
41 37
42static inline void debug_spin_lock_before(spinlock_t *lock) 38static inline void
39debug_spin_lock_before(spinlock_t *lock)
43{ 40{
44 SPIN_BUG_ON(lock->magic != SPINLOCK_MAGIC, lock, "bad magic"); 41 SPIN_BUG_ON(lock->magic != SPINLOCK_MAGIC, lock, "bad magic");
45 SPIN_BUG_ON(lock->owner == current, lock, "recursion"); 42 SPIN_BUG_ON(lock->owner == current, lock, "recursion");
@@ -118,20 +115,13 @@ void _raw_spin_unlock(spinlock_t *lock)
118 115
119static void rwlock_bug(rwlock_t *lock, const char *msg) 116static void rwlock_bug(rwlock_t *lock, const char *msg)
120{ 117{
121 static long print_once = 1; 118 if (!debug_locks_off())
122 119 return;
123 if (xchg(&print_once, 0)) { 120
124 printk(KERN_EMERG "BUG: rwlock %s on CPU#%d, %s/%d, %p\n", 121 printk(KERN_EMERG "BUG: rwlock %s on CPU#%d, %s/%d, %p\n",
125 msg, raw_smp_processor_id(), current->comm, 122 msg, raw_smp_processor_id(), current->comm,
126 current->pid, lock); 123 current->pid, lock);
127 dump_stack(); 124 dump_stack();
128#ifdef CONFIG_SMP
129 /*
130 * We cannot continue on SMP:
131 */
132 panic("bad locking");
133#endif
134 }
135} 125}
136 126
137#define RWLOCK_BUG_ON(cond, lock, msg) if (unlikely(cond)) rwlock_bug(lock, msg) 127#define RWLOCK_BUG_ON(cond, lock, msg) if (unlikely(cond)) rwlock_bug(lock, msg)