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Subject[patch 07/61] lock validator: better lock debugging
From: Ingo Molnar <mingo@elte.hu>

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 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.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
---
drivers/char/sysrq.c | 2
include/asm-generic/mutex-null.h | 11 -
include/linux/debug_locks.h | 62 ++++++++
include/linux/init_task.h | 1
include/linux/mm.h | 8 -
include/linux/mutex-debug.h | 12 -
include/linux/mutex.h | 6
include/linux/rtmutex.h | 10 -
include/linux/sched.h | 4
init/main.c | 9 +
kernel/exit.c | 5
kernel/fork.c | 4
kernel/mutex-debug.c | 289 +++----------------------------------
kernel/mutex-debug.h | 87 +----------
kernel/mutex.c | 83 +++++++---
kernel/mutex.h | 18 --
kernel/rtmutex-debug.c | 302 +--------------------------------------
kernel/rtmutex-debug.h | 8 -
kernel/rtmutex.c | 45 ++---
kernel/rtmutex.h | 3
kernel/sched.c | 16 +-
lib/Kconfig.debug | 26 ++-
lib/Makefile | 2
lib/debug_locks.c | 45 +++++
lib/spinlock_debug.c | 60 +++----
mm/vmalloc.c | 2
26 files changed, 329 insertions(+), 791 deletions(-)

Index: linux/drivers/char/sysrq.c
===================================================================
--- linux.orig/drivers/char/sysrq.c
+++ linux/drivers/char/sysrq.c
@@ -152,7 +152,7 @@ static struct sysrq_key_op sysrq_mountro
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,
Index: linux/include/asm-generic/mutex-null.h
===================================================================
--- linux.orig/include/asm-generic/mutex-null.h
+++ linux/include/asm-generic/mutex-null.h
@@ -10,14 +10,9 @@
#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_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

Index: linux/include/linux/debug_locks.h
===================================================================
--- /dev/null
+++ linux/include/linux/debug_locks.h
@@ -0,0 +1,62 @@
+#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_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_WARN_ON(c) DEBUG_WARN_ON(c)
+#else
+# define SMP_DEBUG_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
+
+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)
+{
+}
+
+static inline void debug_show_all_locks(void)
+{
+}
+
+static inline void debug_show_held_locks(struct task_struct *task)
+{
+}
+
+#endif
Index: linux/include/linux/init_task.h
===================================================================
--- linux.orig/include/linux/init_task.h
+++ linux/include/linux/init_task.h
@@ -133,7 +133,6 @@ extern struct group_info init_groups;
.journal_info = NULL, \
.cpu_timers = INIT_CPU_TIMERS(tsk.cpu_timers), \
.fs_excl = ATOMIC_INIT(0), \
- INIT_RT_MUTEXES(tsk) \
}


Index: linux/include/linux/mm.h
===================================================================
--- linux.orig/include/linux/mm.h
+++ linux/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;
@@ -1080,13 +1081,6 @@ static inline void vm_stat_account(struc
}
#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)
Index: linux/include/linux/mutex-debug.h
===================================================================
--- linux.orig/include/linux/mutex-debug.h
+++ linux/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
Index: linux/include/linux/mutex.h
===================================================================
--- linux.orig/include/linux/mutex.h
+++ linux/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) \
Index: linux/include/linux/rtmutex.h
===================================================================
--- linux.orig/include/linux/rtmutex.h
+++ linux/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_mu

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), \
Index: linux/include/linux/sched.h
===================================================================
--- linux.orig/include/linux/sched.h
+++ linux/include/linux/sched.h
@@ -910,10 +910,6 @@ 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
Index: linux/init/main.c
===================================================================
--- linux.orig/init/main.c
+++ linux/init/main.c
@@ -53,6 +53,7 @@
#include <linux/key.h>
#include <linux/root_dev.h>
#include <linux/buffer_head.h>
+#include <linux/debug_locks.h>

#include <asm/io.h>
#include <asm/bugs.h>
@@ -512,6 +513,14 @@ asmlinkage void __init start_kernel(void
panic(panic_later, panic_param);
profile_init();
local_irq_enable();
+
+ /*
+ * 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) {
Index: linux/kernel/exit.c
===================================================================
--- linux.orig/kernel/exit.c
+++ linux/kernel/exit.c
@@ -952,10 +952,9 @@ fastcall NORET_TYPE void do_exit(long co
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();
Index: linux/kernel/fork.c
===================================================================
--- linux.orig/kernel/fork.c
+++ linux/kernel/fork.c
@@ -921,10 +921,6 @@ static inline void rt_mutex_init_task(st
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
}

Index: linux/kernel/mutex-debug.c
===================================================================
--- linux.orig/kernel/mutex-debug.c
+++ linux/kernel/mutex-debug.c
@@ -19,37 +19,10 @@
#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;
-
static void printk_task(struct task_struct *p)
{
if (p)
@@ -66,157 +39,28 @@ static void printk_ti(struct thread_info
printk("<none>");
}

-static void printk_task_short(struct task_struct *p)
-{
- if (p)
- printk("%s/%d [%p, %3d]", p->comm, p->pid, p, p->prio);
- else
- printk("<none>");
-}
-
static void printk_lock(struct mutex *lock, int print_owner)
{
- printk(" [%p] {%s}\n", lock, lock->name);
+#ifdef CONFIG_PROVE_MUTEX_LOCKING
+ printk(" [%p] {%s}\n", lock, lock->dep_map.name);
+#else
+ printk(" [%p]\n", lock);
+#endif

if (print_owner && lock->owner) {
printk(".. held by: ");
printk_ti(lock->owner);
printk("\n");
}
- if (lock->owner) {
- printk("... acquired at: ");
- print_symbol("%s\n", lock->acquire_ip);
- }
-}
-
-/*
- * printk locks held by a task:
- */
-static void show_task_locks(struct task_struct *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->blocked_on) {
- struct mutex *lock = p->blocked_on->lock;
-
- printk(" blocked on mutex:");
- printk_lock(lock, 1);
- } else
- printk(" (not blocked on mutex)\n");
-}
-
-/*
- * printk all locks held in the system (if filter == NULL),
- * or all locks belonging to a single task (if filter != NULL):
- */
-void show_held_locks(struct task_struct *filter)
-{
- struct list_head *curr, *cursor = NULL;
- struct mutex *lock;
- struct thread_info *t;
- unsigned long flags;
- int count = 0;
-
- if (filter) {
- printk("------------------------------\n");
- printk("| showing all locks held by: | (");
- printk_task_short(filter);
- printk("):\n");
- printk("------------------------------\n");
- } else {
- printk("---------------------------\n");
- printk("| showing all locks held: |\n");
- printk("---------------------------\n");
- }
-
- /*
- * Play safe and acquire the global trace lock. We
- * cannot printk with that lock held so we iterate
- * very carefully:
- */
-next:
- debug_spin_lock_save(&debug_mutex_lock, flags);
- list_for_each(curr, &debug_mutex_held_locks) {
- if (cursor && curr != cursor)
- continue;
- lock = list_entry(curr, struct mutex, held_list);
- t = lock->owner;
- if (filter && (t != filter->thread_info))
- continue;
- count++;
- cursor = curr->next;
- debug_spin_unlock_restore(&debug_mutex_lock, flags);
-
- printk("\n#%03d: ", count);
- printk_lock(lock, filter ? 0 : 1);
- goto next;
- }
- debug_spin_unlock_restore(&debug_mutex_lock, flags);
- printk("\n");
-}
-
-void mutex_debug_show_all_locks(void)
-{
- struct task_struct *g, *p;
- int count = 10;
- int unlock = 1;
-
- printk("\nShowing all blocking locks in the system:\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");
- show_held_locks(NULL);
- printk("=============================================\n\n");
-
- if (unlock)
- read_unlock(&tasklist_lock);
}

static void report_deadlock(struct task_struct *task, struct mutex *lock,
- struct mutex *lockblk, unsigned long ip)
+ struct mutex *lockblk)
{
printk("\n%s/%d is trying to acquire this lock:\n",
current->comm, current->pid);
printk_lock(lock, 1);
- printk("... trying at: ");
- print_symbol("%s\n", ip);
- show_held_locks(current);
+ debug_show_held_locks(current);

if (lockblk) {
printk("but %s/%d is deadlocking current task %s/%d!\n\n",
@@ -225,7 +69,7 @@ static void report_deadlock(struct task_
task->comm, task->pid);
printk_lock(lockblk, 1);

- show_held_locks(task);
+ debug_show_held_locks(task);

printk("\n%s/%d's [blocked] stackdump:\n\n",
task->comm, task->pid);
@@ -235,7 +79,7 @@ static void report_deadlock(struct task_
printk("\n%s/%d's [current] stackdump:\n\n",
current->comm, current->pid);
dump_stack();
- mutex_debug_show_all_locks();
+ debug_show_all_locks();
printk("[ turning off deadlock detection. Please report this. ]\n\n");
local_irq_disable();
}
@@ -243,13 +87,12 @@ static void report_deadlock(struct task_
/*
* Recursively check for mutex deadlocks:
*/
-static int check_deadlock(struct mutex *lock, int depth,
- struct thread_info *ti, unsigned long ip)
+static int check_deadlock(struct mutex *lock, int depth, struct thread_info *ti)
{
struct mutex *lockblk;
struct task_struct *task;

- if (!debug_mutex_on)
+ if (!debug_locks)
return 0;

ti = lock->owner;
@@ -263,123 +106,46 @@ static int check_deadlock(struct mutex *

/* Self-deadlock: */
if (current == task) {
- DEBUG_OFF();
+ debug_locks_off();
if (depth)
return 1;
printk("\n==========================================\n");
printk( "[ BUG: lock recursion deadlock detected! |\n");
printk( "------------------------------------------\n");
- report_deadlock(task, lock, NULL, ip);
+ report_deadlock(task, lock, NULL);
return 0;
}

/* Ugh, something corrupted the lock data structure? */
if (depth > 20) {
- DEBUG_OFF();
+ debug_locks_off();
printk("\n===========================================\n");
printk( "[ BUG: infinite lock dependency detected!? |\n");
printk( "-------------------------------------------\n");
- report_deadlock(task, lock, lockblk, ip);
+ report_deadlock(task, lock, lockblk);
return 0;
}

/* Recursively check for dependencies: */
- if (lockblk && check_deadlock(lockblk, depth+1, ti, ip)) {
+ if (lockblk && check_deadlock(lockblk, depth+1, ti)) {
printk("\n============================================\n");
printk( "[ BUG: circular locking deadlock detected! ]\n");
printk( "--------------------------------------------\n");
- report_deadlock(task, lock, lockblk, ip);
+ report_deadlock(task, lock, lockblk);
return 0;
}
return 0;
}

/*
- * Called when a task exits, this function checks whether the
- * task is holding any locks, and reports the first one if so:
- */
-void mutex_debug_check_no_locks_held(struct task_struct *task)
-{
- struct list_head *curr, *next;
- struct thread_info *t;
- unsigned long flags;
- struct mutex *lock;
-
- if (!debug_mutex_on)
- return;
-
- debug_spin_lock_save(&debug_mutex_lock, flags);
- list_for_each_safe(curr, next, &debug_mutex_held_locks) {
- lock = list_entry(curr, struct mutex, held_list);
- t = lock->owner;
- if (t != task->thread_info)
- continue;
- list_del_init(curr);
- DEBUG_OFF();
- debug_spin_unlock_restore(&debug_mutex_lock, flags);
-
- printk("BUG: %s/%d, lock held at task exit time!\n",
- task->comm, task->pid);
- printk_lock(lock, 1);
- if (lock->owner != task->thread_info)
- printk("exiting task is not even the owner??\n");
- return;
- }
- debug_spin_unlock_restore(&debug_mutex_lock, flags);
-}
-
-/*
- * Called when kernel memory is freed (or unmapped), or if a mutex
- * is destroyed or reinitialized - this code checks whether there is
- * any held lock in the memory range of <from> to <to>:
- */
-void mutex_debug_check_no_locks_freed(const void *from, unsigned long len)
-{
- struct list_head *curr, *next;
- const void *to = from + len;
- unsigned long flags;
- struct mutex *lock;
- void *lock_addr;
-
- if (!debug_mutex_on)
- return;
-
- debug_spin_lock_save(&debug_mutex_lock, flags);
- list_for_each_safe(curr, next, &debug_mutex_held_locks) {
- lock = list_entry(curr, struct mutex, held_list);
- lock_addr = lock;
- if (lock_addr < from || lock_addr >= to)
- continue;
- list_del_init(curr);
- DEBUG_OFF();
- debug_spin_unlock_restore(&debug_mutex_lock, flags);
-
- 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 (lock->owner != current_thread_info())
- printk("freeing task is not even the owner??\n");
- return;
- }
- debug_spin_unlock_restore(&debug_mutex_lock, flags);
-}
-
-/*
* 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_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, 0x11, sizeof(*waiter));
waiter->magic = waiter;
@@ -401,10 +167,12 @@ void debug_mutex_free_waiter(struct mute
}

void debug_mutex_add_waiter(struct mutex *lock, struct mutex_waiter *waiter,
- struct thread_info *ti __IP_DECL__)
+ struct thread_info *ti)
{
SMP_DEBUG_WARN_ON(!spin_is_locked(&lock->wait_lock));
- check_deadlock(lock, 0, ti, ip);
+#ifdef CONFIG_DEBUG_MUTEX_DEADLOCKS
+ check_deadlock(lock, 0, ti);
+#endif
/* Mark the current thread as blocked on the lock: */
ti->task->blocked_on = waiter;
waiter->lock = lock;
@@ -424,13 +192,10 @@ void mutex_remove_waiter(struct mutex *l

void debug_mutex_unlock(struct mutex *lock)
{
+ DEBUG_WARN_ON(lock->owner != current_thread_info());
DEBUG_WARN_ON(lock->magic != lock);
DEBUG_WARN_ON(!lock->wait_list.prev && !lock->wait_list.next);
DEBUG_WARN_ON(lock->owner != current_thread_info());
- if (debug_mutex_on) {
- DEBUG_WARN_ON(list_empty(&lock->held_list));
- list_del_init(&lock->held_list);
- }
}

void debug_mutex_init(struct mutex *lock, const char *name)
@@ -438,10 +203,8 @@ void debug_mutex_init(struct mutex *lock
/*
* 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;
}

Index: linux/kernel/mutex-debug.h
===================================================================
--- linux.orig/kernel/mutex-debug.h
+++ linux/kernel/mutex-debug.h
@@ -10,110 +10,43 @@
* 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)
-
#define spin_lock_mutex(lock, flags) \
do { \
struct mutex *l = container_of(lock, struct mutex, wait_lock); \
\
DEBUG_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_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_WARN_ON(c) \
-do { \
- if (unlikely(c && debug_mutex_on)) { \
- DEBUG_OFF(); \
- WARN_ON(1); \
- } \
-} while (0)
-
-# define DEBUG_BUG_ON(c) \
-do { \
- if (unlikely(c)) \
- DEBUG_BUG(); \
-} while (0)
-
-#ifdef CONFIG_SMP
-# define SMP_DEBUG_WARN_ON(c) DEBUG_WARN_ON(c)
-# define SMP_DEBUG_BUG_ON(c) DEBUG_BUG_ON(c)
-#else
-# define SMP_DEBUG_WARN_ON(c) do { } while (0)
-# define SMP_DEBUG_BUG_ON(c) do { } while (0)
-#endif
-
Index: linux/kernel/mutex.c
===================================================================
--- linux.orig/kernel/mutex.c
+++ linux/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_cou
*
* 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
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
@@ -116,22 +117,36 @@ void fastcall __sched mutex_unlock(struc

EXPORT_SYMBOL(mutex_unlock);

+static void fastcall noinline __sched
+__mutex_unlock_non_nested_slowpath(atomic_t *lock_count);
+
+void fastcall __sched mutex_unlock_non_nested(struct mutex *lock)
+{
+ /*
+ * The unlocking fastpath is the 0->1 transition from 'locked'
+ * into 'unlocked' state:
+ */
+ __mutex_fastpath_unlock(&lock->count, __mutex_unlock_non_nested_slowpath);
+}
+
+EXPORT_SYMBOL(mutex_unlock_non_nested);
+
+
/*
* 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 subtype)
{
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 +188,7 @@ __mutex_lock_common(struct mutex *lock,

/* 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 +198,41 @@ __mutex_lock_common(struct mutex *lock,

debug_mutex_free_waiter(&waiter);

- DEBUG_WARN_ON(list_empty(&lock->held_list));
DEBUG_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);
}

+#ifdef CONFIG_DEBUG_MUTEXES
+void __sched
+mutex_lock_nested(struct mutex *lock, unsigned int subtype)
+{
+ might_sleep();
+ __mutex_lock_common(lock, TASK_UNINTERRUPTIBLE, subtype);
+}
+
+EXPORT_SYMBOL_GPL(mutex_lock_nested);
+#endif
+
/*
* 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, int nested)
{
struct mutex *lock = container_of(lock_count, struct mutex, count);
unsigned long flags;

- DEBUG_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 +242,6 @@ __mutex_unlock_slowpath(atomic_t *lock_c
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 +259,27 @@ __mutex_unlock_slowpath(atomic_t *lock_c
}

/*
+ * Release the lock, slowpath:
+ */
+static fastcall noinline void
+__mutex_unlock_slowpath(atomic_t *lock_count)
+{
+ __mutex_unlock_common_slowpath(lock_count, 1);
+}
+
+static fastcall noinline void
+__mutex_unlock_non_nested_slowpath(atomic_t *lock_count)
+{
+ __mutex_unlock_common_slowpath(lock_count, 0);
+}
+
+
+/*
* 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 +302,11 @@ int fastcall __sched mutex_lock_interrup
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 +323,8 @@ static inline int __mutex_trylock_slowpa

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);
Index: linux/kernel/mutex.h
===================================================================
--- linux.orig/kernel/mutex.h
+++ linux/kernel/mutex.h
@@ -19,19 +19,15 @@
#define DEBUG_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 mutex_acquire(lock, subtype, trylock) do { } while (0)
+#define mutex_release(lock, nested) 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)
+{
+}
Index: linux/kernel/rtmutex-debug.c
===================================================================
--- linux.orig/kernel/rtmutex-debug.c
+++ linux/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
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(struc
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 r

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)
Index: linux/kernel/rtmutex-debug.h
===================================================================
--- linux.orig/kernel/rtmutex-debug.h
+++ linux/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);
Index: linux/kernel/rtmutex.c
===================================================================
--- linux.orig/kernel/rtmutex.c
+++ linux/kernel/rtmutex.c
@@ -160,8 +160,7 @@ int max_lock_depth = 1024;
static int rt_mutex_adjust_prio_chain(task_t *task,
int deadlock_detect,
struct rt_mutex *orig_lock,
- struct rt_mutex_waiter *orig_waiter
- __IP_DECL__)
+ struct rt_mutex_waiter *orig_waiter)
{
struct rt_mutex *lock;
struct rt_mutex_waiter *waiter, *top_waiter = orig_waiter;
@@ -356,7 +355,7 @@ static inline int try_to_steal_lock(stru
*
* 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
@@ -383,7 +382,7 @@ static int try_to_take_rt_mutex(struct r
return 0;

/* We got the lock. */
- debug_rt_mutex_lock(lock __IP__);
+ debug_rt_mutex_lock(lock);

rt_mutex_set_owner(lock, current, 0);

@@ -401,8 +400,7 @@ static int try_to_take_rt_mutex(struct r
*/
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);
@@ -450,8 +448,7 @@ static int task_blocks_on_rt_mutex(struc

spin_unlock(&lock->wait_lock);

- res = rt_mutex_adjust_prio_chain(owner, detect_deadlock, lock,
- waiter __IP__);
+ res = rt_mutex_adjust_prio_chain(owner, detect_deadlock, lock, waiter);

spin_lock(&lock->wait_lock);

@@ -523,7 +520,7 @@ static void wakeup_next_waiter(struct rt
* 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;
@@ -564,7 +561,7 @@ static void remove_waiter(struct rt_mute

spin_unlock(&lock->wait_lock);

- rt_mutex_adjust_prio_chain(owner, 0, lock, NULL __IP__);
+ rt_mutex_adjust_prio_chain(owner, 0, lock, NULL);

spin_lock(&lock->wait_lock);
}
@@ -575,7 +572,7 @@ static void remove_waiter(struct rt_mute
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;
@@ -586,7 +583,7 @@ rt_mutex_slowlock(struct rt_mutex *lock,
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;
}
@@ -600,7 +597,7 @@ rt_mutex_slowlock(struct rt_mutex *lock,

for (;;) {
/* Try to acquire the lock: */
- if (try_to_take_rt_mutex(lock __IP__))
+ if (try_to_take_rt_mutex(lock))
break;

/*
@@ -624,7 +621,7 @@ rt_mutex_slowlock(struct rt_mutex *lock,
*/
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
@@ -650,7 +647,7 @@ rt_mutex_slowlock(struct rt_mutex *lock,
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
@@ -681,7 +678,7 @@ rt_mutex_slowlock(struct rt_mutex *lock,
* 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;

@@ -689,7 +686,7 @@ rt_mutex_slowtrylock(struct rt_mutex *lo

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.
@@ -739,13 +736,13 @@ rt_mutex_fastlock(struct rt_mutex *lock,
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
@@ -753,24 +750,24 @@ rt_mutex_timed_fastlock(struct rt_mutex
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
@@ -918,7 +915,7 @@ void rt_mutex_init_proxy_locked(struct r
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);
}
Index: linux/kernel/rtmutex.h
===================================================================
--- linux.orig/kernel/rtmutex.h
+++ linux/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)
Index: linux/kernel/sched.c
===================================================================
--- linux.orig/kernel/sched.c
+++ linux/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>
@@ -3158,12 +3159,13 @@ void fastcall add_preempt_count(int val)
/*
* Underflow?
*/
- BUG_ON((preempt_count() < 0));
+ if (DEBUG_WARN_ON((preempt_count() < 0)))
+ return;
preempt_count() += val;
/*
* Spinlock count overflowing soon?
*/
- BUG_ON((preempt_count() & PREEMPT_MASK) >= PREEMPT_MASK-10);
+ DEBUG_WARN_ON((preempt_count() & PREEMPT_MASK) >= PREEMPT_MASK-10);
}
EXPORT_SYMBOL(add_preempt_count);

@@ -3172,11 +3174,15 @@ void fastcall sub_preempt_count(int val)
/*
* Underflow?
*/
- BUG_ON(val > preempt_count());
+ if (DEBUG_WARN_ON(val > preempt_count()))
+ return;
/*
* Is the spinlock portion underflowing?
*/
- BUG_ON((val < PREEMPT_MASK) && !(preempt_count() & PREEMPT_MASK));
+ if (DEBUG_WARN_ON((val < PREEMPT_MASK) &&
+ !(preempt_count() & PREEMPT_MASK)))
+ return;
+
preempt_count() -= val;
}
EXPORT_SYMBOL(sub_preempt_count);
@@ -4715,7 +4721,7 @@ void show_state(void)
} while_each_thread(g, p);

read_unlock(&tasklist_lock);
- mutex_debug_show_all_locks();
+ debug_show_all_locks();
}

/**
Index: linux/lib/Kconfig.debug
===================================================================
--- linux.orig/lib/Kconfig.debug
+++ linux/lib/Kconfig.debug
@@ -130,12 +130,30 @@ config DEBUG_PREEMPT
will detect preemption count underflows.

config DEBUG_MUTEXES
- bool "Mutex debugging, deadlock detection"
- default n
+ bool "Mutex debugging, basic checks"
+ default y
depends on DEBUG_KERNEL
help
- This allows mutex semantics violations and mutex related deadlocks
- (lockups) to be detected and reported automatically.
+ This feature allows mutex semantics violations to be detected and
+ reported.
+
+config DEBUG_MUTEX_ALLOC
+ bool "Detect incorrect freeing of live mutexes"
+ default y
+ depends on DEBUG_MUTEXES
+ help
+ This feature will check whether any held mutex is incorrectly
+ freed by the kernel, via any of the memory-freeing routines
+ (kfree(), kmem_cache_free(), free_pages(), vfree(), etc.),
+ or whether there is any lock held during task exit.
+
+config DEBUG_MUTEX_DEADLOCKS
+ bool "Detect mutex related deadlocks"
+ default y
+ depends on DEBUG_MUTEXES
+ help
+ This feature will automatically detect and report mutex related
+ deadlocks, as they happen.

config DEBUG_RT_MUTEXES
bool "RT Mutex debugging, deadlock detection"
Index: linux/lib/Makefile
===================================================================
--- linux.orig/lib/Makefile
+++ linux/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
Index: linux/lib/debug_locks.c
===================================================================
--- /dev/null
+++ linux/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;
+}
Index: linux/lib/spinlock_debug.c
===================================================================
--- linux.orig/lib/spinlock_debug.c
+++ linux/lib/spinlock_debug.c
@@ -9,38 +9,35 @@
#include <linux/config.h>
#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");
@@ -119,20 +116,13 @@ 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)
Index: linux/mm/vmalloc.c
===================================================================
--- linux.orig/mm/vmalloc.c
+++ linux/mm/vmalloc.c
@@ -330,6 +330,8 @@ void __vunmap(void *addr, int deallocate
return;
}

+ debug_check_no_locks_freed(addr, area->size);
+
if (deallocate_pages) {
int i;

-
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