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Commit fbda00ce authored by Prateek Sood's avatar Prateek Sood Committed by Gerrit - the friendly Code Review server
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lockdep: disable lockdep logging 



When lockdep reports a locking error, it disables global
debug_locks which results in other lock debugging features
getting disabled.

Disable only lockdep logging once a locking error is reported.
This will help in tracking lock owners and their stacks from
ramdumps even when lockdep is not reporting them on console.

Change-Id: Ie7b6aa57df84aaa4cf90fc912969d4ca49f77997
Signed-off-by: default avatarPrateek Sood <prsood@codeaurora.org>
parent 65ab504d

kernel/locking/lockdep.c

+76 −47
Original line number Diff line number Diff line
@@ -73,7 +73,29 @@ module_param(lock_stat, int, 0644); 
#define lock_stat 0

#endif



static int lockdep_log = 1;



static int lockdep_logging_off(void)

{

	if (lockdep_log && xchg(&lockdep_log, 0)) {

		if (!debug_locks_silent)

			return 1;

	}

	return 0;

}



#define MAX_ITR 20

#define lockdep_warn_on(cond)						\

({									\

	int __ret = 0;							\

									\

	if (!oops_in_progress && unlikely(cond)) {                      \

		if (lockdep_logging_off() && !debug_locks_silent)       \

			WARN(1, "lockdep_warn_on(%s)", #cond);          \

		__ret = 1;						\

	}								\

	__ret;								\

})



/*

 * lockdep_lock: protects the lockdep graph, the hashes and the
@@ -110,7 +132,7 @@ static inline int graph_unlock(void) 
		 * The lockdep graph lock isn't locked while we expect it to

		 * be, we're confused now, bye!

		 */

		return DEBUG_LOCKS_WARN_ON(1);

		return lockdep_warn_on(1);

	}



	current->lockdep_recursion--;
@@ -118,6 +140,14 @@ static inline int graph_unlock(void) 
	return 0;

}



static int lockdep_logging_off_graph_unlock(void)

{

	int ret = lockdep_logging_off();



	graph_unlock();

	return ret;

}



/*

 * Turn lock debugging off and return with 0 if it was off already,

 * and also release the graph lock:
@@ -149,7 +179,7 @@ static inline struct lock_class *hlock_class(struct held_lock *hlock) 
		/*

		 * Someone passed in garbage, we give up.

		 */

		DEBUG_LOCKS_WARN_ON(1);

		lockdep_warn_on(1);

		return NULL;

	}

	return lock_classes + hlock->class_idx - 1;
@@ -416,7 +446,7 @@ static int save_trace(struct stack_trace *trace) 
	nr_stack_trace_entries += trace->nr_entries;



	if (nr_stack_trace_entries >= MAX_STACK_TRACE_ENTRIES-1) {

		if (!debug_locks_off_graph_unlock())

		if (!lockdep_logging_off_graph_unlock())

			return 0;



		print_lockdep_off("BUG: MAX_STACK_TRACE_ENTRIES too low!");
@@ -723,10 +753,8 @@ static bool assign_lock_key(struct lockdep_map *lock) 
		lock->key = (void *)lock;

	else {

		/* Debug-check: all keys must be persistent! */

		debug_locks_off();

		pr_err("INFO: trying to register non-static key.\n");

		pr_err("the code is fine but needs lockdep annotation.\n");

		pr_err("turning off the locking correctness validator.\n");

		dump_stack();

		return false;

	}
@@ -1196,7 +1224,7 @@ static noinline int print_circular_bug(struct lock_list *this, 
	struct lock_list *first_parent;

	int depth;



	if (!debug_locks_off_graph_unlock() || debug_locks_silent)

	if (!lockdep_logging_off_graph_unlock() || debug_locks_silent)

		return 0;



	if (!save_trace(&this->trace))
@@ -1511,7 +1539,7 @@ print_bad_irq_dependency(struct task_struct *curr, 
			 enum lock_usage_bit bit2,

			 const char *irqclass)

{

	if (!debug_locks_off_graph_unlock() || debug_locks_silent)

	if (!lockdep_logging_off_graph_unlock() || debug_locks_silent)

		return 0;



	pr_warn("\n");
@@ -1740,7 +1768,7 @@ static int 
print_deadlock_bug(struct task_struct *curr, struct held_lock *prev,

		   struct held_lock *next)

{

	if (!debug_locks_off_graph_unlock() || debug_locks_silent)

	if (!lockdep_logging_off_graph_unlock() || debug_locks_silent)

		return 0;



	pr_warn("\n");
@@ -2003,7 +2031,7 @@ check_prevs_add(struct task_struct *curr, struct held_lock *next) 
	}

	return 1;

out_bug:

	if (!debug_locks_off_graph_unlock())

	if (!lockdep_logging_off_graph_unlock())

		return 0;



	/*
@@ -2133,7 +2161,7 @@ static int check_no_collision(struct task_struct *curr, 


	i = get_first_held_lock(curr, hlock);



	if (DEBUG_LOCKS_WARN_ON(chain->depth != curr->lockdep_depth - (i - 1))) {

	if (lockdep_warn_on(chain->depth != curr->lockdep_depth - (i - 1))) {

		print_collision(curr, hlock, chain);

		return 0;

	}
@@ -2141,7 +2169,7 @@ static int check_no_collision(struct task_struct *curr, 
	for (j = 0; j < chain->depth - 1; j++, i++) {

		id = curr->held_locks[i].class_idx - 1;



		if (DEBUG_LOCKS_WARN_ON(chain_hlocks[chain->base + j] != id)) {

		if (lockdep_warn_on(chain_hlocks[chain->base + j] != id)) {

			print_collision(curr, hlock, chain);

			return 0;

		}
@@ -2510,7 +2538,7 @@ static int 
print_usage_bug(struct task_struct *curr, struct held_lock *this,

		enum lock_usage_bit prev_bit, enum lock_usage_bit new_bit)

{

	if (!debug_locks_off_graph_unlock() || debug_locks_silent)

	if (!lockdep_logging_off_graph_unlock() || debug_locks_silent)

		return 0;



	pr_warn("\n");
@@ -2575,7 +2603,7 @@ print_irq_inversion_bug(struct task_struct *curr, 
	struct lock_list *middle = NULL;

	int depth;



	if (!debug_locks_off_graph_unlock() || debug_locks_silent)

	if (!lockdep_logging_off_graph_unlock() || debug_locks_silent)

		return 0;



	pr_warn("\n");
@@ -3135,7 +3163,7 @@ static int mark_lock(struct task_struct *curr, struct held_lock *this, 
		debug_atomic_dec(nr_unused_locks);

		break;

	default:

		if (!debug_locks_off_graph_unlock())

		if (!lockdep_logging_off_graph_unlock())

			return 0;

		WARN_ON(1);

		return 0;
@@ -3174,7 +3202,7 @@ static void __lockdep_init_map(struct lockdep_map *lock, const char *name, 
	/*

	 * Can't be having no nameless bastards around this place!

	 */

	if (DEBUG_LOCKS_WARN_ON(!name)) {

	if (lockdep_warn_on(!name)) {

		lock->name = "NULL";

		return;

	}
@@ -3184,17 +3212,22 @@ static void __lockdep_init_map(struct lockdep_map *lock, const char *name, 
	/*

	 * No key, no joy, we need to hash something.

	 */

	if (DEBUG_LOCKS_WARN_ON(!key))

	if (lockdep_warn_on(!key))

		return;

	/*

	 * Sanity check, the lock-class key must be persistent:

	 */

	if (!static_obj(key)) {

		/*

		 * to make sure register_lock_class returns NULL

		 * for a non static key

		 */

		lock->key = key;

		printk("BUG: key %px not in .data!\n", key);

		/*

		 * What it says above ^^^^^, I suggest you read it.

		 */

		DEBUG_LOCKS_WARN_ON(1);

		lockdep_warn_on(1);

		return;

	}

	lock->key = key;
@@ -3205,7 +3238,7 @@ static void __lockdep_init_map(struct lockdep_map *lock, const char *name, 
	if (subclass) {

		unsigned long flags;



		if (DEBUG_LOCKS_WARN_ON(current->lockdep_recursion))

		if (lockdep_warn_on(current->lockdep_recursion))

			return;



		raw_local_irq_save(flags);
@@ -3231,9 +3264,7 @@ print_lock_nested_lock_not_held(struct task_struct *curr, 
				struct held_lock *hlock,

				unsigned long ip)

{

	if (!debug_locks_off())

		return 0;

	if (debug_locks_silent)

	if (!lockdep_logging_off() || debug_locks_silent)

		return 0;



	pr_warn("\n");
@@ -3378,7 +3409,7 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass, 
	 * Plain impossible, we just registered it and checked it weren't no

	 * NULL like.. I bet this mushroom I ate was good!

	 */

	if (DEBUG_LOCKS_WARN_ON(!class))

	if (lockdep_warn_on(!class))

		return 0;

	hlock->class_idx = class_idx;

	hlock->acquire_ip = ip;
@@ -3428,7 +3459,7 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass, 
		/*

		 * How can we have a chain hash when we ain't got no keys?!

		 */

		if (DEBUG_LOCKS_WARN_ON(chain_key != 0))

		if (lockdep_warn_on(chain_key != 0))

			return 0;

		chain_head = 1;

	}
@@ -3476,9 +3507,7 @@ static int 
print_unlock_imbalance_bug(struct task_struct *curr, struct lockdep_map *lock,

			   unsigned long ip)

{

	if (!debug_locks_off())

		return 0;

	if (debug_locks_silent)

	if (!lockdep_logging_off() || debug_locks_silent)

		return 0;



	pr_warn("\n");
@@ -3527,7 +3556,7 @@ static int match_held_lock(const struct held_lock *hlock, 
		 * State got messed up, follow the sites that change ->references

		 * and try to make sense of it.

		 */

		if (DEBUG_LOCKS_WARN_ON(!hlock->nest_lock))

		if (lockdep_warn_on(!hlock->nest_lock))

			return 0;



		if (hlock->class_idx == class - lock_classes + 1)
@@ -3608,7 +3637,7 @@ __lock_set_class(struct lockdep_map *lock, const char *name, 
	 * This function is about (re)setting the class of a held lock,

	 * yet we're not actually holding any locks. Naughty user!

	 */

	if (DEBUG_LOCKS_WARN_ON(!depth))

	if (lockdep_warn_on(!depth))

		return 0;



	hlock = find_held_lock(curr, lock, depth, &i);
@@ -3617,6 +3646,9 @@ __lock_set_class(struct lockdep_map *lock, const char *name, 


	lockdep_init_map(lock, name, key, 0);

	class = register_lock_class(lock, subclass, 0);

	if (!class)

		return 0;



	hlock->class_idx = class - lock_classes + 1;



	curr->lockdep_depth = i;
@@ -3629,7 +3661,7 @@ __lock_set_class(struct lockdep_map *lock, const char *name, 
	 * I took it apart and put it back together again, except now I have

	 * these 'spare' parts.. where shall I put them.

	 */

	if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth))

	if (lockdep_warn_on(curr->lockdep_depth != depth))

		return 0;

	return 1;

}
@@ -3649,7 +3681,7 @@ static int __lock_downgrade(struct lockdep_map *lock, unsigned long ip) 
	 * This function is about (re)setting the class of a held lock,

	 * yet we're not actually holding any locks. Naughty user!

	 */

	if (DEBUG_LOCKS_WARN_ON(!depth))

	if (lockdep_warn_on(!depth))

		return 0;



	hlock = find_held_lock(curr, lock, depth, &i);
@@ -3671,7 +3703,7 @@ static int __lock_downgrade(struct lockdep_map *lock, unsigned long ip) 
	 * I took it apart and put it back together again, except now I have

	 * these 'spare' parts.. where shall I put them.

	 */

	if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth))

	if (lockdep_warn_on(curr->lockdep_depth != depth))

		return 0;

	return 1;

}
@@ -3699,7 +3731,7 @@ __lock_release(struct lockdep_map *lock, int nested, unsigned long ip) 
	 * So we're all set to release this lock.. wait what lock? We don't

	 * own any locks, you've been drinking again?

	 */

	if (DEBUG_LOCKS_WARN_ON(depth <= 0))

	if (lockdep_warn_on(depth <= 0))

		return print_unlock_imbalance_bug(curr, lock, ip);



	/*
@@ -3743,7 +3775,7 @@ __lock_release(struct lockdep_map *lock, int nested, unsigned long ip) 
	 * We had N bottles of beer on the wall, we drank one, but now

	 * there's not N-1 bottles of beer left on the wall...

	 */

	if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth - 1))

	if (lockdep_warn_on(curr->lockdep_depth != depth - 1))

		return 0;



	return 1;
@@ -4042,9 +4074,7 @@ static int 
print_lock_contention_bug(struct task_struct *curr, struct lockdep_map *lock,

			   unsigned long ip)

{

	if (!debug_locks_off())

		return 0;

	if (debug_locks_silent)

	if (!lockdep_logging_off() || debug_locks_silent)

		return 0;



	pr_warn("\n");
@@ -4081,7 +4111,7 @@ __lock_contended(struct lockdep_map *lock, unsigned long ip) 
	 * Whee, we contended on this lock, except it seems we're not

	 * actually trying to acquire anything much at all..

	 */

	if (DEBUG_LOCKS_WARN_ON(!depth))

	if (lockdep_warn_on(!depth))

		return;



	hlock = find_held_lock(curr, lock, depth, &i);
@@ -4123,7 +4153,7 @@ __lock_acquired(struct lockdep_map *lock, unsigned long ip) 
	 * Yay, we acquired ownership of this lock we didn't try to

	 * acquire, how the heck did that happen?

	 */

	if (DEBUG_LOCKS_WARN_ON(!depth))

	if (lockdep_warn_on(!depth))

		return;



	hlock = find_held_lock(curr, lock, depth, &i);
@@ -4336,7 +4366,7 @@ void lockdep_reset_lock(struct lockdep_map *lock) 
				match |= class == lock->class_cache[j];



			if (unlikely(match)) {

				if (debug_locks_off_graph_unlock()) {

				if (lockdep_logging_off_graph_unlock()) {

					/*

					 * We all just reset everything, how did it match?

					 */
@@ -4385,9 +4415,7 @@ static void 
print_freed_lock_bug(struct task_struct *curr, const void *mem_from,

		     const void *mem_to, struct held_lock *hlock)

{

	if (!debug_locks_off())

		return;

	if (debug_locks_silent)

	if (!lockdep_logging_off() || debug_locks_silent)

		return;



	pr_warn("\n");
@@ -4443,9 +4471,7 @@ EXPORT_SYMBOL_GPL(debug_check_no_locks_freed); 


static void print_held_locks_bug(void)

{

	if (!debug_locks_off())

		return;

	if (debug_locks_silent)

	if (!lockdep_logging_off() || debug_locks_silent)

		return;



	pr_warn("\n");
@@ -4512,7 +4538,7 @@ asmlinkage __visible void lockdep_sys_exit(void) 
	struct task_struct *curr = current;



	if (unlikely(curr->lockdep_depth)) {

		if (!debug_locks_off())

		if (!lockdep_logging_off())

			return;

		pr_warn("\n");

		pr_warn("================================================\n");
@@ -4535,6 +4561,9 @@ void lockdep_rcu_suspicious(const char *file, const int line, const char *s) 
{

	struct task_struct *curr = current;



	if (!lockdep_logging_off())

		return;



	/* Note: the following can be executed concurrently, so be careful. */

	pr_warn("\n");

	pr_warn("=============================\n");