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Commit 60a6ca6c authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge branch 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 

Pull locking fixes from Ingo Molnar:
 "Two lockdep fixes for bugs introduced by the cross-release dependency
  tracking feature - plus a commit that disables it because performance
  regressed in an absymal fashion on some systems"

* 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  locking/lockdep: Disable cross-release features for now
  locking/selftest: Avoid false BUG report
  locking/lockdep: Fix stacktrace mess
parents 2b34218e b483cf3b

kernel/locking/lockdep.c

+20 −28
Original line number Diff line number Diff line
@@ -1873,10 +1873,10 @@ check_prev_add(struct task_struct *curr, struct held_lock *prev, 
	       struct held_lock *next, int distance, struct stack_trace *trace,

	       int (*save)(struct stack_trace *trace))

{

	struct lock_list *uninitialized_var(target_entry);

	struct lock_list *entry;

	int ret;

	struct lock_list this;

	struct lock_list *uninitialized_var(target_entry);

	int ret;



	/*

	 * Prove that the new <prev> -> <next> dependency would not
@@ -1890,8 +1890,17 @@ check_prev_add(struct task_struct *curr, struct held_lock *prev, 
	this.class = hlock_class(next);

	this.parent = NULL;

	ret = check_noncircular(&this, hlock_class(prev), &target_entry);

	if (unlikely(!ret))

	if (unlikely(!ret)) {

		if (!trace->entries) {

			/*

			 * If @save fails here, the printing might trigger

			 * a WARN but because of the !nr_entries it should

			 * not do bad things.

			 */

			save(trace);

		}

		return print_circular_bug(&this, target_entry, next, prev, trace);

	}

	else if (unlikely(ret < 0))

		return print_bfs_bug(ret);
@@ -1938,7 +1947,7 @@ check_prev_add(struct task_struct *curr, struct held_lock *prev, 
		return print_bfs_bug(ret);





	if (save && !save(trace))

	if (!trace->entries && !save(trace))

		return 0;



	/*
@@ -1958,20 +1967,6 @@ check_prev_add(struct task_struct *curr, struct held_lock *prev, 
	if (!ret)

		return 0;



	/*

	 * Debugging printouts:

	 */

	if (verbose(hlock_class(prev)) || verbose(hlock_class(next))) {

		graph_unlock();

		printk("\n new dependency: ");

		print_lock_name(hlock_class(prev));

		printk(KERN_CONT " => ");

		print_lock_name(hlock_class(next));

		printk(KERN_CONT "\n");

		dump_stack();

		if (!graph_lock())

			return 0;

	}

	return 2;

}
@@ -1986,8 +1981,12 @@ check_prevs_add(struct task_struct *curr, struct held_lock *next) 
{

	int depth = curr->lockdep_depth;

	struct held_lock *hlock;

	struct stack_trace trace;

	int (*save)(struct stack_trace *trace) = save_trace;

	struct stack_trace trace = {

		.nr_entries = 0,

		.max_entries = 0,

		.entries = NULL,

		.skip = 0,

	};



	/*

	 * Debugging checks.
@@ -2018,17 +2017,10 @@ check_prevs_add(struct task_struct *curr, struct held_lock *next) 
			 */

			if (hlock->read != 2 && hlock->check) {

				int ret = check_prev_add(curr, hlock, next,

							 distance, &trace, save);

							 distance, &trace, save_trace);

				if (!ret)

					return 0;



				/*

				 * Stop saving stack_trace if save_trace() was

				 * called at least once:

				 */

				if (save && ret == 2)

					save = NULL;



				/*

				 * Stop after the first non-trylock entry,

				 * as non-trylock entries have added their

lib/Kconfig.debug

+2 −2
Original line number Diff line number Diff line
@@ -1092,8 +1092,8 @@ config PROVE_LOCKING 
	select DEBUG_MUTEXES

	select DEBUG_RT_MUTEXES if RT_MUTEXES

	select DEBUG_LOCK_ALLOC

	select LOCKDEP_CROSSRELEASE

	select LOCKDEP_COMPLETIONS

	select LOCKDEP_CROSSRELEASE if BROKEN

	select LOCKDEP_COMPLETIONS if BROKEN

	select TRACE_IRQFLAGS

	default n

	help

lib/locking-selftest.c

+2 −0
Original line number Diff line number Diff line
@@ -2031,11 +2031,13 @@ void locking_selftest(void) 
	print_testname("mixed read-lock/lock-write ABBA");

	pr_cont("             |");

	dotest(rlock_ABBA1, FAILURE, LOCKTYPE_RWLOCK);

#ifdef CONFIG_PROVE_LOCKING

	/*

	 * Lockdep does indeed fail here, but there's nothing we can do about

	 * that now.  Don't kill lockdep for it.

	 */

	unexpected_testcase_failures--;

#endif



	pr_cont("             |");

	dotest(rwsem_ABBA1, FAILURE, LOCKTYPE_RWSEM);