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[PATCH] lockdep: better lock debugging

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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>
This commit is contained in:
Ingo Molnar 2006-07-03 00:24:33 -07:00 committed by Linus Torvalds
parent fb7e42413a
commit 9a11b49a80
25 changed files with 264 additions and 566 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

2
drivers/char/sysrq.c
View file

@ -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
View file

@ -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 Normal file
View file

@ -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
View file

@ -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
View file

@ -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
View file

@ -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
View file

@ -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
View file

@ -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
View file

@ -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
View file

@ -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
View file

@ -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
View file

@ -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
View file

@ -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
View file

@ -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
View file

@ -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
View file

@ -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
View file

@ -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
View file

@ -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
View file

@ -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
View file

@ -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
View file

@ -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
View file

@ -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 Normal file
View file

@ -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;
}

60
lib/spinlock_debug.c
View file

@ -8,38 +8,35 @@
#include <linux/spinlock.h>
#include <linux/interrupt.h>
#include <linux/debug_locks.h>
#include <linux/delay.h>
#include <linux/module.h>
static void spin_bug(spinlock_t *lock, const char *msg)
{
static long print_once = 1;
struct task_struct *owner = NULL;
if (xchg(&print_once, 0)) {
if (lock->owner && lock->owner != SPINLOCK_OWNER_INIT)
owner = lock->owner;
printk(KERN_EMERG "BUG: spinlock %s on CPU#%d, %s/%d\n",
msg, raw_smp_processor_id(),
current->comm, current->pid);
printk(KERN_EMERG " lock: %p, .magic: %08x, .owner: %s/%d, "
".owner_cpu: %d\n",
lock, lock->magic,
owner ? owner->comm : "<none>",
owner ? owner->pid : -1,
lock->owner_cpu);
dump_stack();
#ifdef CONFIG_SMP
/*
* We cannot continue on SMP:
*/
// panic("bad locking");
#endif
}
if (!debug_locks_off())
return;
if (lock->owner && lock->owner != SPINLOCK_OWNER_INIT)
owner = lock->owner;
printk(KERN_EMERG "BUG: spinlock %s on CPU#%d, %s/%d\n",
msg, raw_smp_processor_id(),
current->comm, current->pid);
printk(KERN_EMERG " lock: %p, .magic: %08x, .owner: %s/%d, "
".owner_cpu: %d\n",
lock, lock->magic,
owner ? owner->comm : "<none>",
owner ? owner->pid : -1,
lock->owner_cpu);
dump_stack();
}
#define SPIN_BUG_ON(cond, lock, msg) if (unlikely(cond)) spin_bug(lock, msg)
static inline void debug_spin_lock_before(spinlock_t *lock)
static inline void
debug_spin_lock_before(spinlock_t *lock)
{
SPIN_BUG_ON(lock->magic != SPINLOCK_MAGIC, lock, "bad magic");
SPIN_BUG_ON(lock->owner == current, lock, "recursion");
@ -118,20 +115,13 @@ void _raw_spin_unlock(spinlock_t *lock)
static void rwlock_bug(rwlock_t *lock, const char *msg)
{
static long print_once = 1;
if (!debug_locks_off())
return;
if (xchg(&print_once, 0)) {
printk(KERN_EMERG "BUG: rwlock %s on CPU#%d, %s/%d, %p\n",
msg, raw_smp_processor_id(), current->comm,
current->pid, lock);
dump_stack();
#ifdef CONFIG_SMP
/*
* We cannot continue on SMP:
*/
panic("bad locking");
#endif
}
printk(KERN_EMERG "BUG: rwlock %s on CPU#%d, %s/%d, %p\n",
msg, raw_smp_processor_id(), current->comm,
current->pid, lock);
dump_stack();
}
#define RWLOCK_BUG_ON(cond, lock, msg) if (unlikely(cond)) rwlock_bug(lock, msg)

2
mm/vmalloc.c
View file

@ -330,6 +330,8 @@ void __vunmap(void *addr, int deallocate_pages)
return;
}
debug_check_no_locks_freed(addr, area->size);
if (deallocate_pages) {
int i;