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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>
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commit 9a11b49a805665e13a56aa067afaf81d43ec1514 1 parent fb7e424
Ingo Molnar authored Linus Torvalds committed
2  drivers/char/sysrq.c
View
@@ -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
@@ -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
View
@@ -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
@@ -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
@@ -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
@@ -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
@@ -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
@@ -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
@@ -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
@@ -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
@@ -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
@@ -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
@@ -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
@@ -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
@@ -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 =
@@ -237,11 +231,20 @@ __mutex_unlock_slowpath(atomic_t *lock_count __IP_DECL__)
}
/*
+ * 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
@@ -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
@@ -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
@@ -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
@@ -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
@@ -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
@@ -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
@@ -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
View
@@ -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
View
@@ -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 (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
- }
+ if (!debug_locks_off())
+ return;
+
+ 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
@@ -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;
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