diff options
author | Ingo Molnar <mingo@elte.hu> | 2006-07-03 09:24:33 +0200 |
---|---|---|
committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-07-04 00:27:01 +0200 |
commit | 9a11b49a805665e13a56aa067afaf81d43ec1514 (patch) | |
tree | bf499956e3f67d1211d68ab1e2eb76645f453dfb /kernel/rtmutex-debug.c | |
parent | [PATCH] lockdep: remove mutex deadlock checking code (diff) | |
download | linux-9a11b49a805665e13a56aa067afaf81d43ec1514.tar.xz linux-9a11b49a805665e13a56aa067afaf81d43ec1514.zip |
[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>
Diffstat (limited to 'kernel/rtmutex-debug.c')
-rw-r--r-- | kernel/rtmutex-debug.c | 302 |
1 files changed, 15 insertions, 287 deletions
diff --git a/kernel/rtmutex-debug.c b/kernel/rtmutex-debug.c index 4aa8a2c9f453..353a853bc390 100644 --- a/kernel/rtmutex-debug.c +++ b/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(¤t->pi_lock)) \ spin_unlock(¤t->pi_lock); \ - if (spin_is_locked(¤t->held_list_lock)) \ - spin_unlock(¤t->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(¤t->held_list_lock, flags); - list_for_each(curr, ¤t->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(¤t->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(¤t->held_list_lock, flags); - list_add_tail(&lock->held_list_entry, ¤t->held_list_head); - spin_unlock_irqrestore(¤t->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(¤t->held_list_lock, flags); - list_del_init(&lock->held_list_entry); - spin_unlock_irqrestore(¤t->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) |