diff options
| -rw-r--r-- | kernel/mutex-debug.c | 316 | ||||
| -rw-r--r-- | lib/Kconfig.debug | 8 |
2 files changed, 0 insertions, 324 deletions
diff --git a/kernel/mutex-debug.c b/kernel/mutex-debug.c index fe0e9f2..a92de14 100644 --- a/kernel/mutex-debug.c +++ b/kernel/mutex-debug.c @@ -51,321 +51,6 @@ LIST_HEAD(debug_mutex_held_locks); */ int debug_mutex_on = 1; -static void printk_task(struct task_struct *p) -{ - if (p) - printk("%16s:%5d [%p, %3d]", p->comm, p->pid, p, p->prio); - else - printk("<none>"); -} - -static void printk_ti(struct thread_info *ti) -{ - if (ti) - printk_task(ti->task); - else - 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); - - 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) -{ - 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); - - if (lockblk) { - printk("but %s/%d is deadlocking current task %s/%d!\n\n", - task->comm, task->pid, current->comm, current->pid); - printk("\n%s/%d is blocked on this lock:\n", - task->comm, task->pid); - printk_lock(lockblk, 1); - - 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(); - mutex_debug_show_all_locks(); - printk("[ turning off deadlock detection. Please report this. ]\n\n"); - local_irq_disable(); -} - -/* - * Recursively check for mutex deadlocks: - */ -static int check_deadlock(struct mutex *lock, int depth, - struct thread_info *ti, unsigned long ip) -{ - struct mutex *lockblk; - struct task_struct *task; - - if (!debug_mutex_on) - return 0; - - ti = lock->owner; - if (!ti) - return 0; - - task = ti->task; - lockblk = NULL; - if (task->blocked_on) - lockblk = task->blocked_on->lock; - - /* Self-deadlock: */ - if (current == task) { - DEBUG_OFF(); - if (depth) - return 1; - printk("\n==========================================\n"); - printk( "[ BUG: lock recursion deadlock detected! |\n"); - printk( "------------------------------------------\n"); - report_deadlock(task, lock, NULL, ip); - return 0; - } - - /* Ugh, something corrupted the lock data structure? */ - if (depth > 20) { - DEBUG_OFF(); - printk("\n===========================================\n"); - printk( "[ BUG: infinite lock dependency detected!? |\n"); - printk( "-------------------------------------------\n"); - report_deadlock(task, lock, lockblk, ip); - return 0; - } - - /* Recursively check for dependencies: */ - if (lockblk && check_deadlock(lockblk, depth+1, ti, ip)) { - printk("\n============================================\n"); - printk( "[ BUG: circular locking deadlock detected! ]\n"); - printk( "--------------------------------------------\n"); - report_deadlock(task, lock, lockblk, ip); - 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. */ @@ -405,7 +90,6 @@ void debug_mutex_add_waiter(struct mutex *lock, struct mutex_waiter *waiter, struct thread_info *ti __IP_DECL__) { SMP_DEBUG_LOCKS_WARN_ON(!spin_is_locked(&lock->wait_lock)); - check_deadlock(lock, 0, ti, ip); /* Mark the current thread as blocked on the lock: */ ti->task->blocked_on = waiter; waiter->lock = lock; diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index e4fcbd1..7b3863d 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -115,14 +115,6 @@ config DEBUG_PREEMPT if kernel code uses it in a preemption-unsafe way. Also, the kernel will detect preemption count underflows. -config DEBUG_MUTEXES - bool "Mutex debugging, deadlock detection" - default n - depends on DEBUG_KERNEL - help - This allows mutex semantics violations and mutex related deadlocks - (lockups) to be detected and reported automatically. - config DEBUG_RT_MUTEXES bool "RT Mutex debugging, deadlock detection" depends on DEBUG_KERNEL && RT_MUTEXES |
