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[PATCH] lockdep: better lock debugging

Generic lock debugging:

 - generalized lock debugging framework. For example, a bug in one lock
   subsystem turns off debugging in all lock subsystems.

 - got rid of the caller address passing (__IP__/__IP_DECL__/etc.) from
   the mutex/rtmutex debugging code: it caused way too much prototype
   hackery, and lockdep will give the same information anyway.

 - ability to do silent tests

 - check lock freeing in vfree too.

 - more finegrained debugging options, to allow distributions to
   turn off more expensive debugging features.

There's no separate 'held mutexes' list anymore - but there's a 'held locks'
stack within lockdep, which unifies deadlock detection across all lock
classes.  (this is independent of the lockdep validation stuff - lockdep first
checks whether we are holding a lock already)

Here are the current debugging options:

CONFIG_DEBUG_MUTEXES=y
CONFIG_DEBUG_LOCK_ALLOC=y

which do:

 config DEBUG_MUTEXES
          bool "Mutex debugging, basic checks"

 config DEBUG_LOCK_ALLOC
         bool "Detect incorrect freeing of live mutexes"

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
master
Ingo Molnar 16 years ago
committed by Linus Torvalds
parent
commit
9a11b49a80
  1. 2
      drivers/char/sysrq.c
  2. 15
      include/asm-generic/mutex-null.h
  3. 69
      include/linux/debug_locks.h
  4. 1
      include/linux/init_task.h
  5. 8
      include/linux/mm.h
  6. 12
      include/linux/mutex-debug.h
  7. 6
      include/linux/mutex.h
  8. 10
      include/linux/rtmutex.h
  9. 4
      include/linux/sched.h
  10. 8
      init/main.c
  11. 5
      kernel/exit.c
  12. 4
      kernel/fork.c
  13. 51
      kernel/mutex-debug.c
  14. 82
      kernel/mutex-debug.h
  15. 52
      kernel/mutex.c
  16. 17
      kernel/mutex.h
  17. 302
      kernel/rtmutex-debug.c
  18. 8
      kernel/rtmutex-debug.h
  19. 46
      kernel/rtmutex.c
  20. 3
      kernel/rtmutex.h
  21. 16
      kernel/sched.c
  22. 2
      lib/Makefile
  23. 45
      lib/debug_locks.c
  24. 62
      lib/spinlock_debug.c
  25. 2
      mm/vmalloc.c

2
drivers/char/sysrq.c

@ -151,7 +151,7 @@ static struct sysrq_key_op sysrq_mountro_op = {
static void sysrq_handle_showlocks(int key, struct pt_regs *pt_regs,
struct tty_struct *tty)
{
mutex_debug_show_all_locks();
debug_show_all_locks();
}
static struct sysrq_key_op sysrq_showlocks_op = {
.handler = sysrq_handle_showlocks,

15
include/asm-generic/mutex-null.h

@ -10,15 +10,10 @@
#ifndef _ASM_GENERIC_MUTEX_NULL_H
#define _ASM_GENERIC_MUTEX_NULL_H
/* extra parameter only needed for mutex debugging: */
#ifndef __IP__
# define __IP__
#endif
#define __mutex_fastpath_lock(count, fail_fn) fail_fn(count __RET_IP__)
#define __mutex_fastpath_lock_retval(count, fail_fn) fail_fn(count __RET_IP__)
#define __mutex_fastpath_unlock(count, fail_fn) fail_fn(count __RET_IP__)
#define __mutex_fastpath_trylock(count, fail_fn) fail_fn(count)
#define __mutex_slowpath_needs_to_unlock() 1
#define __mutex_fastpath_lock(count, fail_fn) fail_fn(count)
#define __mutex_fastpath_lock_retval(count, fail_fn) fail_fn(count)
#define __mutex_fastpath_unlock(count, fail_fn) fail_fn(count)
#define __mutex_fastpath_trylock(count, fail_fn) fail_fn(count)
#define __mutex_slowpath_needs_to_unlock() 1
#endif

69
include/linux/debug_locks.h

@ -0,0 +1,69 @@
#ifndef __LINUX_DEBUG_LOCKING_H
#define __LINUX_DEBUG_LOCKING_H
extern int debug_locks;
extern int debug_locks_silent;
/*
* Generic 'turn off all lock debugging' function:
*/
extern int debug_locks_off(void);
/*
* In the debug case we carry the caller's instruction pointer into
* other functions, but we dont want the function argument overhead
* in the nondebug case - hence these macros:
*/
#define _RET_IP_ (unsigned long)__builtin_return_address(0)
#define _THIS_IP_ ({ __label__ __here; __here: (unsigned long)&&__here; })
#define DEBUG_LOCKS_WARN_ON(c) \
({ \
int __ret = 0; \
\
if (unlikely(c)) { \
if (debug_locks_off()) \
WARN_ON(1); \
__ret = 1; \
} \
__ret; \
})
#ifdef CONFIG_SMP
# define SMP_DEBUG_LOCKS_WARN_ON(c) DEBUG_LOCKS_WARN_ON(c)
#else
# define SMP_DEBUG_LOCKS_WARN_ON(c) do { } while (0)
#endif
#ifdef CONFIG_DEBUG_LOCKING_API_SELFTESTS
extern void locking_selftest(void);
#else
# define locking_selftest() do { } while (0)
#endif
#ifdef CONFIG_LOCKDEP
extern void debug_show_all_locks(void);
extern void debug_show_held_locks(struct task_struct *task);
extern void debug_check_no_locks_freed(const void *from, unsigned long len);
extern void debug_check_no_locks_held(struct task_struct *task);
#else
static inline void debug_show_all_locks(void)
{
}
static inline void debug_show_held_locks(struct task_struct *task)
{
}
static inline void
debug_check_no_locks_freed(const void *from, unsigned long len)
{
}
static inline void
debug_check_no_locks_held(struct task_struct *task)
{
}
#endif
#endif

1
include/linux/init_task.h

@ -124,7 +124,6 @@ extern struct group_info init_groups;
.cpu_timers = INIT_CPU_TIMERS(tsk.cpu_timers), \
.fs_excl = ATOMIC_INIT(0), \
.pi_lock = SPIN_LOCK_UNLOCKED, \
INIT_RT_MUTEXES(tsk) \
}

8
include/linux/mm.h

@ -14,6 +14,7 @@
#include <linux/prio_tree.h>
#include <linux/fs.h>
#include <linux/mutex.h>
#include <linux/debug_locks.h>
struct mempolicy;
struct anon_vma;
@ -1034,13 +1035,6 @@ static inline void vm_stat_account(struct mm_struct *mm,
}
#endif /* CONFIG_PROC_FS */
static inline void
debug_check_no_locks_freed(const void *from, unsigned long len)
{
mutex_debug_check_no_locks_freed(from, len);
rt_mutex_debug_check_no_locks_freed(from, len);
}
#ifndef CONFIG_DEBUG_PAGEALLOC
static inline void
kernel_map_pages(struct page *page, int numpages, int enable)

12
include/linux/mutex-debug.h

@ -7,17 +7,11 @@
* Mutexes - debugging helpers:
*/
#define __DEBUG_MUTEX_INITIALIZER(lockname) \
, .held_list = LIST_HEAD_INIT(lockname.held_list), \
.name = #lockname , .magic = &lockname
#define __DEBUG_MUTEX_INITIALIZER(lockname) \
, .magic = &lockname
#define mutex_init(sem) __mutex_init(sem, __FUNCTION__)
#define mutex_init(sem) __mutex_init(sem, __FILE__":"#sem)
extern void FASTCALL(mutex_destroy(struct mutex *lock));
extern void mutex_debug_show_all_locks(void);
extern void mutex_debug_show_held_locks(struct task_struct *filter);
extern void mutex_debug_check_no_locks_held(struct task_struct *task);
extern void mutex_debug_check_no_locks_freed(const void *from, unsigned long len);
#endif

6
include/linux/mutex.h

@ -50,8 +50,6 @@ struct mutex {
struct list_head wait_list;
#ifdef CONFIG_DEBUG_MUTEXES
struct thread_info *owner;
struct list_head held_list;
unsigned long acquire_ip;
const char *name;
void *magic;
#endif
@ -76,10 +74,6 @@ struct mutex_waiter {
# define __DEBUG_MUTEX_INITIALIZER(lockname)
# define mutex_init(mutex) __mutex_init(mutex, NULL)
# define mutex_destroy(mutex) do { } while (0)
# define mutex_debug_show_all_locks() do { } while (0)
# define mutex_debug_show_held_locks(p) do { } while (0)
# define mutex_debug_check_no_locks_held(task) do { } while (0)
# define mutex_debug_check_no_locks_freed(from, len) do { } while (0)
#endif
#define __MUTEX_INITIALIZER(lockname) \

10
include/linux/rtmutex.h

@ -29,8 +29,6 @@ struct rt_mutex {
struct task_struct *owner;
#ifdef CONFIG_DEBUG_RT_MUTEXES
int save_state;
struct list_head held_list_entry;
unsigned long acquire_ip;
const char *name, *file;
int line;
void *magic;
@ -98,14 +96,6 @@ extern int rt_mutex_trylock(struct rt_mutex *lock);
extern void rt_mutex_unlock(struct rt_mutex *lock);
#ifdef CONFIG_DEBUG_RT_MUTEXES
# define INIT_RT_MUTEX_DEBUG(tsk) \
.held_list_head = LIST_HEAD_INIT(tsk.held_list_head), \
.held_list_lock = SPIN_LOCK_UNLOCKED
#else
# define INIT_RT_MUTEX_DEBUG(tsk)
#endif
#ifdef CONFIG_RT_MUTEXES
# define INIT_RT_MUTEXES(tsk) \
.pi_waiters = PLIST_HEAD_INIT(tsk.pi_waiters, tsk.pi_lock), \

4
include/linux/sched.h

@ -865,10 +865,6 @@ struct task_struct {
struct plist_head pi_waiters;
/* Deadlock detection and priority inheritance handling */
struct rt_mutex_waiter *pi_blocked_on;
# ifdef CONFIG_DEBUG_RT_MUTEXES
spinlock_t held_list_lock;
struct list_head held_list_head;
# endif
#endif
#ifdef CONFIG_DEBUG_MUTEXES

8
init/main.c

@ -47,6 +47,7 @@
#include <linux/key.h>
#include <linux/unwind.h>
#include <linux/buffer_head.h>
#include <linux/debug_locks.h>
#include <asm/io.h>
#include <asm/bugs.h>
@ -511,6 +512,13 @@ asmlinkage void __init start_kernel(void)
console_init();
if (panic_later)
panic(panic_later, panic_param);
/*
* Need to run this when irqs are enabled, because it wants
* to self-test [hard/soft]-irqs on/off lock inversion bugs
* too:
*/
locking_selftest();
#ifdef CONFIG_BLK_DEV_INITRD
if (initrd_start && !initrd_below_start_ok &&
initrd_start < min_low_pfn << PAGE_SHIFT) {

5
kernel/exit.c

@ -933,10 +933,9 @@ fastcall NORET_TYPE void do_exit(long code)
if (unlikely(current->pi_state_cache))
kfree(current->pi_state_cache);
/*
* If DEBUG_MUTEXES is on, make sure we are holding no locks:
* Make sure we are holding no locks:
*/
mutex_debug_check_no_locks_held(tsk);
rt_mutex_debug_check_no_locks_held(tsk);
debug_check_no_locks_held(tsk);
if (tsk->io_context)
exit_io_context();

4
kernel/fork.c

@ -919,10 +919,6 @@ static inline void rt_mutex_init_task(struct task_struct *p)
spin_lock_init(&p->pi_lock);
plist_head_init(&p->pi_waiters, &p->pi_lock);
p->pi_blocked_on = NULL;
# ifdef CONFIG_DEBUG_RT_MUTEXES
spin_lock_init(&p->held_list_lock);
INIT_LIST_HEAD(&p->held_list_head);
# endif
#endif
}

51
kernel/mutex-debug.c

@ -20,52 +20,19 @@
#include <linux/spinlock.h>
#include <linux/kallsyms.h>
#include <linux/interrupt.h>
#include <linux/debug_locks.h>
#include "mutex-debug.h"
/*
* We need a global lock when we walk through the multi-process
* lock tree. Only used in the deadlock-debugging case.
*/
DEFINE_SPINLOCK(debug_mutex_lock);
/*
* All locks held by all tasks, in a single global list:
*/
LIST_HEAD(debug_mutex_held_locks);
/*
* In the debug case we carry the caller's instruction pointer into
* other functions, but we dont want the function argument overhead
* in the nondebug case - hence these macros:
*/
#define __IP_DECL__ , unsigned long ip
#define __IP__ , ip
#define __RET_IP__ , (unsigned long)__builtin_return_address(0)
/*
* "mutex debugging enabled" flag. We turn it off when we detect
* the first problem because we dont want to recurse back
* into the tracing code when doing error printk or
* executing a BUG():
*/
int debug_mutex_on = 1;
/*
* Must be called with lock->wait_lock held.
*/
void debug_mutex_set_owner(struct mutex *lock,
struct thread_info *new_owner __IP_DECL__)
void debug_mutex_set_owner(struct mutex *lock, struct thread_info *new_owner)
{
lock->owner = new_owner;
DEBUG_LOCKS_WARN_ON(!list_empty(&lock->held_list));
if (debug_mutex_on) {
list_add_tail(&lock->held_list, &debug_mutex_held_locks);
lock->acquire_ip = ip;
}
}
void debug_mutex_init_waiter(struct mutex_waiter *waiter)
void debug_mutex_lock_common(struct mutex *lock, struct mutex_waiter *waiter)
{
memset(waiter, MUTEX_DEBUG_INIT, sizeof(*waiter));
waiter->magic = waiter;
@ -87,9 +54,10 @@ void debug_mutex_free_waiter(struct mutex_waiter *waiter)
}
void debug_mutex_add_waiter(struct mutex *lock, struct mutex_waiter *waiter,
struct thread_info *ti __IP_DECL__)
struct thread_info *ti)
{
SMP_DEBUG_LOCKS_WARN_ON(!spin_is_locked(&lock->wait_lock));
/* Mark the current thread as blocked on the lock: */
ti->task->blocked_on = waiter;
waiter->lock = lock;
@ -109,13 +77,10 @@ void mutex_remove_waiter(struct mutex *lock, struct mutex_waiter *waiter,
void debug_mutex_unlock(struct mutex *lock)
{
DEBUG_LOCKS_WARN_ON(lock->owner != current_thread_info());
DEBUG_LOCKS_WARN_ON(lock->magic != lock);
DEBUG_LOCKS_WARN_ON(!lock->wait_list.prev && !lock->wait_list.next);
DEBUG_LOCKS_WARN_ON(lock->owner != current_thread_info());
if (debug_mutex_on) {
DEBUG_LOCKS_WARN_ON(list_empty(&lock->held_list));
list_del_init(&lock->held_list);
}
}
void debug_mutex_init(struct mutex *lock, const char *name)
@ -123,10 +88,8 @@ void debug_mutex_init(struct mutex *lock, const char *name)
/*
* Make sure we are not reinitializing a held lock:
*/
mutex_debug_check_no_locks_freed((void *)lock, sizeof(*lock));
debug_check_no_locks_freed((void *)lock, sizeof(*lock));
lock->owner = NULL;
INIT_LIST_HEAD(&lock->held_list);
lock->name = name;
lock->magic = lock;
}

82
kernel/mutex-debug.h

@ -10,102 +10,44 @@
* More details are in kernel/mutex-debug.c.
*/
extern spinlock_t debug_mutex_lock;
extern struct list_head debug_mutex_held_locks;
extern int debug_mutex_on;
/*
* In the debug case we carry the caller's instruction pointer into
* other functions, but we dont want the function argument overhead
* in the nondebug case - hence these macros:
*/
#define __IP_DECL__ , unsigned long ip
#define __IP__ , ip
#define __RET_IP__ , (unsigned long)__builtin_return_address(0)
/*
* This must be called with lock->wait_lock held.
*/
extern void debug_mutex_set_owner(struct mutex *lock,
struct thread_info *new_owner __IP_DECL__);
extern void
debug_mutex_set_owner(struct mutex *lock, struct thread_info *new_owner);
static inline void debug_mutex_clear_owner(struct mutex *lock)
{
lock->owner = NULL;
}
extern void debug_mutex_init_waiter(struct mutex_waiter *waiter);
extern void debug_mutex_lock_common(struct mutex *lock,
struct mutex_waiter *waiter);
extern void debug_mutex_wake_waiter(struct mutex *lock,
struct mutex_waiter *waiter);
extern void debug_mutex_free_waiter(struct mutex_waiter *waiter);
extern void debug_mutex_add_waiter(struct mutex *lock,
struct mutex_waiter *waiter,
struct thread_info *ti __IP_DECL__);
struct thread_info *ti);
extern void mutex_remove_waiter(struct mutex *lock, struct mutex_waiter *waiter,
struct thread_info *ti);
extern void debug_mutex_unlock(struct mutex *lock);
extern void debug_mutex_init(struct mutex *lock, const char *name);
#define debug_spin_lock_save(lock, flags) \
do { \
local_irq_save(flags); \
if (debug_mutex_on) \
spin_lock(lock); \
} while (0)
#define debug_spin_unlock_restore(lock, flags) \
do { \
if (debug_mutex_on) \
spin_unlock(lock); \
local_irq_restore(flags); \
preempt_check_resched(); \
} while (0)
extern void debug_mutex_init(struct mutex *lock, const char *name,
struct lock_class_key *key);
#define spin_lock_mutex(lock, flags) \
do { \
struct mutex *l = container_of(lock, struct mutex, wait_lock); \
\
DEBUG_LOCKS_WARN_ON(in_interrupt()); \
debug_spin_lock_save(&debug_mutex_lock, flags); \
spin_lock(lock); \
local_irq_save(flags); \
__raw_spin_lock(&(lock)->raw_lock); \
DEBUG_LOCKS_WARN_ON(l->magic != l); \
} while (0)
#define spin_unlock_mutex(lock, flags) \
do { \
spin_unlock(lock); \
debug_spin_unlock_restore(&debug_mutex_lock, flags); \
__raw_spin_unlock(&(lock)->raw_lock); \
local_irq_restore(flags); \
preempt_check_resched(); \
} while (0)
#define DEBUG_OFF() \
do { \
if (debug_mutex_on) { \
debug_mutex_on = 0; \
console_verbose(); \
if (spin_is_locked(&debug_mutex_lock)) \
spin_unlock(&debug_mutex_lock); \
} \
} while (0)
#define DEBUG_BUG() \
do { \
if (debug_mutex_on) { \
DEBUG_OFF(); \
BUG(); \
} \
} while (0)
#define DEBUG_LOCKS_WARN_ON(c) \
do { \
if (unlikely(c && debug_mutex_on)) { \
DEBUG_OFF(); \
WARN_ON(1); \
} \
} while (0)
#ifdef CONFIG_SMP
# define SMP_DEBUG_LOCKS_WARN_ON(c) DEBUG_LOCKS_WARN_ON(c)
#else
# define SMP_DEBUG_LOCKS_WARN_ON(c) do { } while (0)
#endif

52
kernel/mutex.c

@ -17,6 +17,7 @@
#include <linux/module.h>
#include <linux/spinlock.h>
#include <linux/interrupt.h>
#include <linux/debug_locks.h>
/*
* In the DEBUG case we are using the "NULL fastpath" for mutexes,
@ -38,7 +39,7 @@
*
* It is not allowed to initialize an already locked mutex.
*/
void fastcall __mutex_init(struct mutex *lock, const char *name)
__always_inline void fastcall __mutex_init(struct mutex *lock, const char *name)
{
atomic_set(&lock->count, 1);
spin_lock_init(&lock->wait_lock);
@ -56,7 +57,7 @@ EXPORT_SYMBOL(__mutex_init);
* branch is predicted by the CPU as default-untaken.
*/
static void fastcall noinline __sched
__mutex_lock_slowpath(atomic_t *lock_count __IP_DECL__);
__mutex_lock_slowpath(atomic_t *lock_count);
/***
* mutex_lock - acquire the mutex
@ -79,7 +80,7 @@ __mutex_lock_slowpath(atomic_t *lock_count __IP_DECL__);
*
* This function is similar to (but not equivalent to) down().
*/
void fastcall __sched mutex_lock(struct mutex *lock)
void inline fastcall __sched mutex_lock(struct mutex *lock)
{
might_sleep();
/*
@ -92,7 +93,7 @@ void fastcall __sched mutex_lock(struct mutex *lock)
EXPORT_SYMBOL(mutex_lock);
static void fastcall noinline __sched
__mutex_unlock_slowpath(atomic_t *lock_count __IP_DECL__);
__mutex_unlock_slowpath(atomic_t *lock_count);
/***
* mutex_unlock - release the mutex
@ -120,18 +121,17 @@ EXPORT_SYMBOL(mutex_unlock);
* Lock a mutex (possibly interruptible), slowpath:
*/
static inline int __sched
__mutex_lock_common(struct mutex *lock, long state __IP_DECL__)
__mutex_lock_common(struct mutex *lock, long state, unsigned int subclass)
{
struct task_struct *task = current;
struct mutex_waiter waiter;
unsigned int old_val;
unsigned long flags;
debug_mutex_init_waiter(&waiter);
spin_lock_mutex(&lock->wait_lock, flags);
debug_mutex_add_waiter(lock, &waiter, task->thread_info, ip);
debug_mutex_lock_common(lock, &waiter);
debug_mutex_add_waiter(lock, &waiter, task->thread_info);
/* add waiting tasks to the end of the waitqueue (FIFO): */
list_add_tail(&waiter.list, &lock->wait_list);
@ -173,7 +173,7 @@ __mutex_lock_common(struct mutex *lock, long state __IP_DECL__)
/* got the lock - rejoice! */
mutex_remove_waiter(lock, &waiter, task->thread_info);
debug_mutex_set_owner(lock, task->thread_info __IP__);
debug_mutex_set_owner(lock, task->thread_info);
/* set it to 0 if there are no waiters left: */
if (likely(list_empty(&lock->wait_list)))
@ -183,32 +183,28 @@ __mutex_lock_common(struct mutex *lock, long state __IP_DECL__)
debug_mutex_free_waiter(&waiter);
DEBUG_LOCKS_WARN_ON(list_empty(&lock->held_list));
DEBUG_LOCKS_WARN_ON(lock->owner != task->thread_info);
return 0;
}
static void fastcall noinline __sched
__mutex_lock_slowpath(atomic_t *lock_count __IP_DECL__)
__mutex_lock_slowpath(atomic_t *lock_count)
{
struct mutex *lock = container_of(lock_count, struct mutex, count);
__mutex_lock_common(lock, TASK_UNINTERRUPTIBLE __IP__);
__mutex_lock_common(lock, TASK_UNINTERRUPTIBLE, 0);
}
/*
* Release the lock, slowpath:
*/
static fastcall noinline void
__mutex_unlock_slowpath(atomic_t *lock_count __IP_DECL__)
static fastcall inline void
__mutex_unlock_common_slowpath(atomic_t *lock_count)
{
struct mutex *lock = container_of(lock_count, struct mutex, count);
unsigned long flags;
DEBUG_LOCKS_WARN_ON(lock->owner != current_thread_info());
spin_lock_mutex(&lock->wait_lock, flags);
debug_mutex_unlock(lock);
/*
* some architectures leave the lock unlocked in the fastpath failure
@ -218,8 +214,6 @@ __mutex_unlock_slowpath(atomic_t *lock_count __IP_DECL__)
if (__mutex_slowpath_needs_to_unlock())
atomic_set(&lock->count, 1);
debug_mutex_unlock(lock);
if (!list_empty(&lock->wait_list)) {
/* get the first entry from the wait-list: */
struct mutex_waiter *waiter =
@ -236,12 +230,21 @@ __mutex_unlock_slowpath(atomic_t *lock_count __IP_DECL__)
spin_unlock_mutex(&lock->wait_lock, flags);
}
/*
* Release the lock, slowpath:
*/
static fastcall noinline void
__mutex_unlock_slowpath(atomic_t *lock_count)
{
__mutex_unlock_common_slowpath(lock_count);
}
/*
* Here come the less common (and hence less performance-critical) APIs:
* mutex_lock_interruptible() and mutex_trylock().
*/
static int fastcall noinline __sched
__mutex_lock_interruptible_slowpath(atomic_t *lock_count __IP_DECL__);
__mutex_lock_interruptible_slowpath(atomic_t *lock_count);
/***
* mutex_lock_interruptible - acquire the mutex, interruptable
@ -264,11 +267,11 @@ int fastcall __sched mutex_lock_interruptible(struct mutex *lock)
EXPORT_SYMBOL(mutex_lock_interruptible);
static int fastcall noinline __sched
__mutex_lock_interruptible_slowpath(atomic_t *lock_count __IP_DECL__)
__mutex_lock_interruptible_slowpath(atomic_t *lock_count)
{
struct mutex *lock = container_of(lock_count, struct mutex, count);
return __mutex_lock_common(lock, TASK_INTERRUPTIBLE __IP__);
return __mutex_lock_common(lock, TASK_INTERRUPTIBLE, 0);
}
/*
@ -285,7 +288,8 @@ static inline int __mutex_trylock_slowpath(atomic_t *lock_count)
prev = atomic_xchg(&lock->count, -1);
if (likely(prev == 1))
debug_mutex_set_owner(lock, current_thread_info() __RET_IP__);
debug_mutex_set_owner(lock, current_thread_info());
/* Set it back to 0 if there are no waiters: */
if (likely(list_empty(&lock->wait_list)))
atomic_set(&lock->count, 0);

17
kernel/mutex.h

@ -16,22 +16,15 @@
#define mutex_remove_waiter(lock, waiter, ti) \
__list_del((waiter)->list.prev, (waiter)->list.next)
#define DEBUG_LOCKS_WARN_ON(c) do { } while (0)
#define debug_mutex_set_owner(lock, new_owner) do { } while (0)
#define debug_mutex_clear_owner(lock) do { } while (0)
#define debug_mutex_init_waiter(waiter) do { } while (0)
#define debug_mutex_wake_waiter(lock, waiter) do { } while (0)
#define debug_mutex_free_waiter(waiter) do { } while (0)
#define debug_mutex_add_waiter(lock, waiter, ti, ip) do { } while (0)
#define debug_mutex_add_waiter(lock, waiter, ti) do { } while (0)
#define debug_mutex_unlock(lock) do { } while (0)
#define debug_mutex_init(lock, name) do { } while (0)
/*
* Return-address parameters/declarations. They are very useful for
* debugging, but add overhead in the !DEBUG case - so we go the
* trouble of using this not too elegant but zero-cost solution:
*/
#define __IP_DECL__
#define __IP__
#define __RET_IP__
static inline void
debug_mutex_lock_common(struct mutex *lock, struct mutex_waiter *waiter)
{
}

302
kernel/rtmutex-debug.c

@ -26,6 +26,7 @@
#include <linux/interrupt.h>
#include <linux/plist.h>
#include <linux/fs.h>
#include <linux/debug_locks.h>
#include "rtmutex_common.h"
@ -45,8 +46,6 @@ do { \
console_verbose(); \
if (spin_is_locked(&current->pi_lock)) \
spin_unlock(&current->pi_lock); \
if (spin_is_locked(&current->held_list_lock)) \
spin_unlock(&current->held_list_lock); \
} \
} while (0)
@ -105,14 +104,6 @@ static void printk_task(task_t *p)
printk("<none>");
}
static void printk_task_short(task_t *p)
{
if (p)
printk("%s/%d [%p, %3d]", p->comm, p->pid, p, p->prio);
else
printk("<none>");
}
static void printk_lock(struct rt_mutex *lock, int print_owner)
{
if (lock->name)
@ -128,222 +119,6 @@ static void printk_lock(struct rt_mutex *lock, int print_owner)
printk_task(rt_mutex_owner(lock));
printk("\n");
}
if (rt_mutex_owner(lock)) {
printk("... acquired at: ");
print_symbol("%s\n", lock->acquire_ip);
}
}
static void printk_waiter(struct rt_mutex_waiter *w)
{
printk("-------------------------\n");
printk("| waiter struct %p:\n", w);
printk("| w->list_entry: [DP:%p/%p|SP:%p/%p|PRI:%d]\n",
w->list_entry.plist.prio_list.prev, w->list_entry.plist.prio_list.next,
w->list_entry.plist.node_list.prev, w->list_entry.plist.node_list.next,
w->list_entry.prio);
printk("| w->pi_list_entry: [DP:%p/%p|SP:%p/%p|PRI:%d]\n",
w->pi_list_entry.plist.prio_list.prev, w->pi_list_entry.plist.prio_list.next,
w->pi_list_entry.plist.node_list.prev, w->pi_list_entry.plist.node_list.next,
w->pi_list_entry.prio);
printk("\n| lock:\n");
printk_lock(w->lock, 1);
printk("| w->ti->task:\n");
printk_task(w->task);
printk("| blocked at: ");
print_symbol("%s\n", w->ip);
printk("-------------------------\n");
}
static void show_task_locks(task_t *p)
{
switch (p->state) {
case TASK_RUNNING: printk("R"); break;
case TASK_INTERRUPTIBLE: printk("S"); break;
case TASK_UNINTERRUPTIBLE: printk("D"); break;
case TASK_STOPPED: printk("T"); break;
case EXIT_ZOMBIE: printk("Z"); break;
case EXIT_DEAD: printk("X"); break;
default: printk("?"); break;
}
printk_task(p);
if (p->pi_blocked_on) {
struct rt_mutex *lock = p->pi_blocked_on->lock;
printk(" blocked on:");
printk_lock(lock, 1);
} else
printk(" (not blocked)\n");
}
void rt_mutex_show_held_locks(task_t *task, int verbose)
{
struct list_head *curr, *cursor = NULL;
struct rt_mutex *lock;
task_t *t;
unsigned long flags;
int count = 0;
if (!rt_trace_on)
return;
if (verbose) {
printk("------------------------------\n");
printk("| showing all locks held by: | (");
printk_task_short(task);
printk("):\n");
printk("------------------------------\n");
}
next:
spin_lock_irqsave(&task->held_list_lock, flags);
list_for_each(curr, &task->held_list_head) {
if (cursor && curr != cursor)
continue;
lock = list_entry(curr, struct rt_mutex, held_list_entry);
t = rt_mutex_owner(lock);
WARN_ON(t != task);
count++;
cursor = curr->next;
spin_unlock_irqrestore(&task->held_list_lock, flags);
printk("\n#%03d: ", count);
printk_lock(lock, 0);
goto next;
}
spin_unlock_irqrestore(&task->held_list_lock, flags);
printk("\n");
}
void rt_mutex_show_all_locks(void)
{
task_t *g, *p;
int count = 10;
int unlock = 1;
printk("\n");
printk("----------------------\n");
printk("| showing all tasks: |\n");
printk("----------------------\n");
/*
* Here we try to get the tasklist_lock as hard as possible,
* if not successful after 2 seconds we ignore it (but keep
* trying). This is to enable a debug printout even if a
* tasklist_lock-holding task deadlocks or crashes.
*/
retry:
if (!read_trylock(&tasklist_lock)) {
if (count == 10)
printk("hm, tasklist_lock locked, retrying... ");
if (count) {
count--;
printk(" #%d", 10-count);
mdelay(200);
goto retry;
}
printk(" ignoring it.\n");
unlock = 0;
}
if (count != 10)
printk(" locked it.\n");
do_each_thread(g, p) {
show_task_locks(p);
if (!unlock)
if (read_trylock(&tasklist_lock))
unlock = 1;
} while_each_thread(g, p);
printk("\n");
printk("-----------------------------------------\n");
printk("| showing all locks held in the system: |\n");
printk("-----------------------------------------\n");
do_each_thread(g, p) {
rt_mutex_show_held_locks(p, 0);
if (!unlock)
if (read_trylock(&tasklist_lock))
unlock = 1;
} while_each_thread(g, p);
printk("=============================================\n\n");
if (unlock)
read_unlock(&tasklist_lock);
}
void rt_mutex_debug_check_no_locks_held(task_t *task)
{
struct rt_mutex_waiter *w;
struct list_head *curr;
struct rt_mutex *lock;
if (!rt_trace_on)
return;
if (!rt_prio(task->normal_prio) && rt_prio(task->prio)) {
printk("BUG: PI priority boost leaked!\n");
printk_task(task);
printk("\n");
}
if (list_empty(&task->held_list_head))
return;
spin_lock(&task->pi_lock);
plist_for_each_entry(w, &task->pi_waiters, pi_list_entry) {
TRACE_OFF();
printk("hm, PI interest held at exit time? Task:\n");
printk_task(task);
printk_waiter(w);
return;
}
spin_unlock(&task->pi_lock);
list_for_each(curr, &task->held_list_head) {
lock = list_entry(curr, struct rt_mutex, held_list_entry);
printk("BUG: %s/%d, lock held at task exit time!\n",
task->comm, task->pid);
printk_lock(lock, 1);
if (rt_mutex_owner(lock) != task)
printk("exiting task is not even the owner??\n");
}
}
int rt_mutex_debug_check_no_locks_freed(const void *from, unsigned long len)
{
const void *to = from + len;
struct list_head *curr;
struct rt_mutex *lock;
unsigned long flags;
void *lock_addr;
if (!rt_trace_on)
return 0;
spin_lock_irqsave(&current->held_list_lock, flags);
list_for_each(curr, &current->held_list_head) {
lock = list_entry(curr, struct rt_mutex, held_list_entry);
lock_addr = lock;
if (lock_addr < from || lock_addr >= to)
continue;
TRACE_OFF();
printk("BUG: %s/%d, active lock [%p(%p-%p)] freed!\n",
current->comm, current->pid, lock, from, to);
dump_stack();
printk_lock(lock, 1);
if (rt_mutex_owner(lock) != current)
printk("freeing task is not even the owner??\n");
return 1;
}
spin_unlock_irqrestore(&current->held_list_lock, flags);
return 0;
}
void rt_mutex_debug_task_free(struct task_struct *task)
@ -395,85 +170,41 @@ void debug_rt_mutex_print_deadlock(struct rt_mutex_waiter *waiter)
current->comm, current->pid);
printk_lock(waiter->lock, 1);
printk("... trying at: ");
print_symbol("%s\n", waiter->ip);
printk("\n2) %s/%d is blocked on this lock:\n", task->comm, task->pid);
printk_lock(waiter->deadlock_lock, 1);
rt_mutex_show_held_locks(current, 1);
rt_mutex_show_held_locks(task, 1);
debug_show_held_locks(current);
debug_show_held_locks(task);
printk("\n%s/%d's [blocked] stackdump:\n\n", task->comm, task->pid);
show_stack(task, NULL);
printk("\n%s/%d's [current] stackdump:\n\n",
current->comm, current->pid);
dump_stack();
rt_mutex_show_all_locks();
debug_show_all_locks();
printk("[ turning off deadlock detection."
"Please report this trace. ]\n\n");
local_irq_disable();
}
void debug_rt_mutex_lock(struct rt_mutex *lock __IP_DECL__)
void debug_rt_mutex_lock(struct rt_mutex *lock)
{
unsigned long flags;
if (rt_trace_on) {
TRACE_WARN_ON_LOCKED(!list_empty(&lock->held_list_entry));
spin_lock_irqsave(&current->held_list_lock, flags);
list_add_tail(&lock->held_list_entry, &current->held_list_head);
spin_unlock_irqrestore(&current->held_list_lock, flags);
lock->acquire_ip = ip;
}
}
void debug_rt_mutex_unlock(struct rt_mutex *lock)
{
unsigned long flags;
if (rt_trace_on) {
TRACE_WARN_ON_LOCKED(rt_mutex_owner(lock) != current);
TRACE_WARN_ON_LOCKED(list_empty(&lock->held_list_entry));
spin_lock_irqsave(&current->held_list_lock, flags);
list_del_init(&lock->held_list_entry);
spin_unlock_irqrestore(&current->held_list_lock, flags);
}
TRACE_WARN_ON_LOCKED(rt_mutex_owner(lock) != current);
}
void debug_rt_mutex_proxy_lock(struct rt_mutex *lock,
struct task_struct *powner __IP_DECL__)
void
debug_rt_mutex_proxy_lock(struct rt_mutex *lock, struct task_struct *powner)
{
unsigned long flags;
if (rt_trace_on) {
TRACE_WARN_ON_LOCKED(!list_empty(&lock->held_list_entry));
spin_lock_irqsave(&powner->held_list_lock, flags);
list_add_tail(&lock->held_list_entry, &powner->held_list_head);
spin_unlock_irqrestore(&powner->held_list_lock, flags);
lock->acquire_ip = ip;
}
}
void debug_rt_mutex_proxy_unlock(struct rt_mutex *lock)
{
unsigned long flags;
if (rt_trace_on) {
struct task_struct *owner = rt_mutex_owner(lock);
TRACE_WARN_ON_LOCKED(!owner);
TRACE_WARN_ON_LOCKED(list_empty(&lock->held_list_entry));
spin_lock_irqsave(&owner->held_list_lock, flags);
list_del_init(&lock->held_list_entry);
spin_unlock_irqrestore(&owner->held_list_lock, flags);
}
TRACE_WARN_ON_LOCKED(!rt_mutex_owner(lock));
}
void debug_rt_mutex_init_waiter(struct rt_mutex_waiter *waiter)
@ -493,14 +224,11 @@ void debug_rt_mutex_free_waiter(struct rt_mutex_waiter *waiter)
void debug_rt_mutex_init(struct rt_mutex *lock, const char *name)
{
void *addr = lock;
if (rt_trace_on) {
rt_mutex_debug_check_no_locks_freed(addr,
sizeof(struct rt_mutex));
INIT_LIST_HEAD(&lock->held_list_entry);
lock->name = name;
}
/*
* Make sure we are not reinitializing a held lock:
*/
debug_check_no_locks_freed((void *)lock, sizeof(*lock));
lock->name = name;
}
void rt_mutex_deadlock_account_lock(struct rt_mutex *lock, task_t *task)

8
kernel/rtmutex-debug.h

@ -9,20 +9,16 @@
* This file contains macros used solely by rtmutex.c. Debug version.
*/
#define __IP_DECL__ , unsigned long ip
#define __IP__ , ip
#define __RET_IP__ , (unsigned long)__builtin_return_address(0)
extern void
rt_mutex_deadlock_account_lock(struct rt_mutex *lock, struct task_struct *task);
extern void rt_mutex_deadlock_account_unlock(struct task_struct *task);
extern void debug_rt_mutex_init_waiter(struct rt_mutex_waiter *waiter);
extern void debug_rt_mutex_free_waiter(struct rt_mutex_waiter *waiter);
extern void debug_rt_mutex_init(struct rt_mutex *lock, const char *name);
extern void debug_rt_mutex_lock(struct rt_mutex *lock __IP_DECL__);
extern void debug_rt_mutex_lock(struct rt_mutex *lock);
extern void debug_rt_mutex_unlock(struct rt_mutex *lock);
extern void debug_rt_mutex_proxy_lock(struct rt_mutex *lock,
struct task_struct *powner __IP_DECL__);
struct task_struct *powner);
extern void debug_rt_mutex_proxy_unlock(struct rt_mutex *lock);
extern void debug_rt_mutex_deadlock(int detect, struct rt_mutex_waiter *waiter,
struct rt_mutex *lock);

46
kernel/rtmutex.c

@ -161,8 +161,7 @@ static int rt_mutex_adjust_prio_chain(task_t *task,
int deadlock_detect,
struct rt_mutex *orig_lock,
struct rt_mutex_waiter *orig_waiter,
struct task_struct *top_task
__IP_DECL__)
struct task_struct *top_task)
{
struct rt_mutex *lock;
struct rt_mutex_waiter *waiter, *top_waiter = orig_waiter;
@ -357,7 +356,7 @@ static inline int try_to_steal_lock(struct rt_mutex *lock)
*
* Must be called with lock->wait_lock held.
*/
static int try_to_take_rt_mutex(struct rt_mutex *lock __IP_DECL__)
static int try_to_take_rt_mutex(struct rt_mutex *lock)
{
/*
* We have to be careful here if the atomic speedups are
@ -384,7 +383,7 @@ static int try_to_take_rt_mutex(struct rt_mutex *lock __IP_DECL__)
return 0;
/* We got the lock. */
debug_rt_mutex_lock(lock __IP__);
debug_rt_mutex_lock(lock);
rt_mutex_set_owner(lock, current, 0);
@ -402,8 +401,7 @@ static int try_to_take_rt_mutex(struct rt_mutex *lock __IP_DECL__)
*/
static int task_blocks_on_rt_mutex(struct rt_mutex *lock,
struct rt_mutex_waiter *waiter,
int detect_deadlock
__IP_DECL__)
int detect_deadlock)
{
struct rt_mutex_waiter *top_waiter = waiter;
task_t *owner = rt_mutex_owner(lock);
@ -454,7 +452,7 @@ static int task_blocks_on_rt_mutex(struct rt_mutex *lock,
spin_unlock(&lock->wait_lock);
res = rt_mutex_adjust_prio_chain(owner, detect_deadlock, lock, waiter,
current __IP__);
current);
spin_lock(&lock->wait_lock);
@ -526,7 +524,7 @@ static void wakeup_next_waiter(struct rt_mutex *lock)
* Must be called with lock->wait_lock held
*/
static void remove_waiter(struct rt_mutex *lock,
struct rt_mutex_waiter *waiter __IP_DECL__)
struct rt_mutex_waiter *waiter)
{
int first = (waiter == rt_mutex_top_waiter(lock));
int boost = 0;
@ -568,7 +566,7 @@ static void remove_waiter(struct rt_mutex *lock,
spin_unlock(&lock->wait_lock);
rt_mutex_adjust_prio_chain(owner, 0, lock, NULL, current __IP__);
rt_mutex_adjust_prio_chain(owner, 0, lock, NULL, current);
spin_lock(&lock->wait_lock);
}
@ -595,7 +593,7 @@ void rt_mutex_adjust_pi(struct task_struct *task)
get_task_struct(task);
spin_unlock_irqrestore(&task->pi_lock, flags);
rt_mutex_adjust_prio_chain(task, 0, NULL, NULL, task __RET_IP__);
rt_mutex_adjust_prio_chain(task, 0, NULL, NULL, task);
}
/*
@ -604,7 +602,7 @@ void rt_mutex_adjust_pi(struct task_struct *task)
static int __sched
rt_mutex_slowlock(struct rt_mutex *lock, int state,
struct hrtimer_sleeper *timeout,
int detect_deadlock __IP_DECL__)
int detect_deadlock)
{
struct rt_mutex_waiter waiter;
int ret = 0;
@ -615,7 +613,7 @@ rt_mutex_slowlock(struct rt_mutex *lock, int state,
spin_lock(&lock->wait_lock);
/* Try to acquire the lock again: */
if (try_to_take_rt_mutex(lock __IP__)) {
if (try_to_take_rt_mutex(lock)) {
spin_unlock(&lock->wait_lock);
return 0;
}
@ -629,7 +627,7 @@ rt_mutex_slowlock(struct rt_mutex *lock, int state,
for (;;) {
/* Try to acquire the lock: */
if (try_to_take_rt_mutex(lock __IP__))
if (try_to_take_rt_mutex(lock))
break;
/*
@ -653,7 +651,7 @@ rt_mutex_slowlock(struct rt_mutex *lock, int state,
*/
if (!waiter.task) {
ret = task_blocks_on_rt_mutex(lock, &waiter,
detect_deadlock __IP__);
detect_deadlock);
/*
* If we got woken up by the owner then start loop
* all over without going into schedule to try
@ -680,7 +678,7 @@ rt_mutex_slowlock(struct rt_mutex *lock, int state,
set_current_state(TASK_RUNNING);
if (unlikely(waiter.task))
remove_waiter(lock, &waiter __IP__);
remove_waiter(lock, &waiter);
/*
* try_to_take_rt_mutex() sets the waiter bit
@ -711,7 +709,7 @@ rt_mutex_slowlock(struct rt_mutex *lock, int state,
* Slow path try-lock function:
*/
static inline int
rt_mutex_slowtrylock(struct rt_mutex *lock __IP_DECL__)
rt_mutex_slowtrylock(struct rt_mutex *lock)
{
int ret = 0;
@ -719,7 +717,7 @@ rt_mutex_slowtrylock(struct rt_mutex *lock __IP_DECL__)
if (likely(rt_mutex_owner(lock) != current)) {
ret = try_to_take_rt_mutex(lock __IP__);
ret = try_to_take_rt_mutex(lock);
/*
* try_to_take_rt_mutex() sets the lock waiters
* bit unconditionally. Clean this up.
@ -769,13 +767,13 @@ rt_mutex_fastlock(struct rt_mutex *lock, int state,
int detect_deadlock,
int (*slowfn)(struct rt_mutex *lock, int state,
struct hrtimer_sleeper *timeout,
int detect_deadlock __IP_DECL__))
int detect_deadlock))
{
if (!detect_deadlock && likely(rt_mutex_cmpxchg(lock, NULL, current))) {
rt_mutex_deadlock_account_lock(lock, current);
return 0;
} else
return slowfn(lock, state, NULL, detect_deadlock __RET_IP__);
return slowfn(lock, state, NULL, detect_deadlock);
}
static inline int
@ -783,24 +781,24 @@ rt_mutex_timed_fastlock(struct rt_mutex *lock, int state,
struct hrtimer_sleeper *timeout, int detect_deadlock,
int (*slowfn)(struct rt_mutex *lock, int state,
struct hrtimer_sleeper *timeout,
int detect_deadlock __IP_DECL__))
int detect_deadlock))
{
if (!detect_deadlock && likely(rt_mutex_cmpxchg(lock, NULL, current))) {
rt_mutex_deadlock_account_lock(lock, current);
return 0;
} else
return slowfn(lock, state, timeout, detect_deadlock __RET_IP__);
return slowfn(lock, state, timeout, detect_deadlock);
}
static inline int
rt_mutex_fasttrylock(struct rt_mutex *lock,
int (*slowfn)(struct rt_mutex *lock __IP_DECL__))
int (*slowfn)(struct rt_mutex *lock))
{
if (likely(rt_mutex_cmpxchg(lock, NULL, current))) {
rt_mutex_deadlock_account_lock(lock, current);
return 1;
}
return slowfn(lock __RET_IP__);
return slowfn(lock);
}
static inline void
@ -948,7 +946,7 @@ void rt_mutex_init_proxy_locked(struct rt_mutex *lock,
struct task_struct *proxy_owner)
{
__rt_mutex_init(lock, NULL);
debug_rt_mutex_proxy_lock(lock, proxy_owner __RET_IP__);
debug_rt_mutex_proxy_lock(lock, proxy_owner);
rt_mutex_set_owner(lock, proxy_owner, 0);
rt_mutex_deadlock_account_lock(lock, proxy_owner);
}

3
kernel/rtmutex.h

@ -10,9 +10,6 @@
* Non-debug version.
*/
#define __IP_DECL__
#define __IP__
#define __RET_IP__
#define rt_mutex_deadlock_check(l) (0)
#define rt_mutex_deadlock_account_lock(m, t) do { } while (0)
#define rt_mutex_deadlock_account_unlock(l) do { } while (0)

16
kernel/sched.c

@ -30,6 +30,7 @@
#include <linux/capability.h>
#include <linux/completion.h>
#include <linux/kernel_stat.h>
#include <linux/debug_locks.h>
#include <linux/security.h>
#include <linux/notifier.h>
#include <linux/profile.h>
@ -3142,12 +3143,13 @@ void fastcall add_preempt_count(int val)
/*
* Underflow?
*/
BUG_ON((preempt_count() < 0));
if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0)))
return;
preempt_count() += val;
/*
* Spinlock count overflowing soon?
*/
BUG_ON((preempt_count() & PREEMPT_MASK) >= PREEMPT_MASK-10);
DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK) >= PREEMPT_MASK-10);
}
EXPORT_SYMBOL(add_preempt_count);
@ -3156,11 +3158,15 @@ void fastcall sub_preempt_count(int val)
/*
* Underflow?
*/
BUG_ON(val > preempt_count());
if (DEBUG_LOCKS_WARN_ON(val > preempt_count()))
return;
/*
* Is the spinlock portion underflowing?
*/
BUG_ON((val < PREEMPT_MASK) && !(preempt_count() & PREEMPT_MASK));
if (DEBUG_LOCKS_WARN_ON((val < PREEMPT_MASK) &&
!(preempt_count() & PREEMPT_MASK)))
return;
preempt_count() -= val;
}
EXPORT_SYMBOL(sub_preempt_count);
@ -4690,7 +4696,7 @@ void show_state(void)
} while_each_thread(g, p);
read_unlock(&tasklist_lock);
mutex_debug_show_all_locks();
debug_show_all_locks();
}
/**

2
lib/Makefile

@ -11,7 +11,7 @@ lib-$(CONFIG_SMP) += cpumask.o
lib-y += kobject.o kref.o kobject_uevent.o klist.o
obj-y += sort.o parser.o halfmd4.o iomap_copy.o
obj-y += sort.o parser.o halfmd4.o iomap_copy.o debug_locks.o
ifeq ($(CONFIG_DEBUG_KOBJECT),y)
CFLAGS_kobject.o += -DDEBUG

45
lib/debug_locks.c

@ -0,0 +1,45 @@
/*
* lib/debug_locks.c
*
* Generic place for common debugging facilities for various locks:
* spinlocks, rwlocks, mutexes and rwsems.
*
* Started by Ingo Molnar:
*
* Copyright (C) 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
*/
#include <linux/rwsem.h>
#include <linux/mutex.h>
#include <linux/module.h>
#include <linux/spinlock.h>
#include <linux/debug_locks.h>
/*
* We want to turn all lock-debugging facilities on/off at once,
* via a global flag. The reason is that once a single bug has been
* detected and reported, there might be cascade of followup bugs
* that would just muddy the log. So we report the first one and
* shut up after that.
*/
int debug_locks = 1;
/*
* The locking-testsuite uses <debug_locks_silent> to get a
* 'silent failure': nothing is printed to the console when
* a locking bug is detected.
*/
int debug_locks_silent;
/*
* Generic 'turn off all lock debugging' function:
*/
int debug_locks_off(void)
{
if (xchg(&debug_locks, 0)) {
if (!debug_locks_silent) {
console_verbose();
return 1;
}
}
return 0;
}

62
lib/spinlock_debug.c

@ -8,38 +8,35 @@
#include <linux/spinlock.h>
#include <linux/interrupt.h>