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Commit 21199f27 authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

locking/lockdep: Fix hlock->pin_count reset on lock stack rebuilds 



Various people reported hitting the "unpinning an unpinned lock"
warning. As it turns out there are 2 places where we take a lock out
of the middle of a stack, and in those cases it would fail to preserve
the pin_count when rebuilding the lock stack.

Reported-by: default avatarSasha Levin <sasha.levin@oracle.com>
Reported-by: default avatarTim Spriggs <tspriggs@apple.com>
Tested-by: default avatarSasha Levin <sasha.levin@oracle.com>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: davej@codemonkey.org.uk
Link: http://lkml.kernel.org/r/20150916141040.GA11639@twins.programming.kicks-ass.net


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent bcee19f4

kernel/locking/lockdep.c

+5 −5
Original line number Diff line number Diff line
@@ -3068,7 +3068,7 @@ static int __lock_is_held(struct lockdep_map *lock); 
static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass,

			  int trylock, int read, int check, int hardirqs_off,

			  struct lockdep_map *nest_lock, unsigned long ip,

			  int references)

			  int references, int pin_count)

{

	struct task_struct *curr = current;

	struct lock_class *class = NULL;
@@ -3157,7 +3157,7 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass, 
	hlock->waittime_stamp = 0;

	hlock->holdtime_stamp = lockstat_clock();

#endif

	hlock->pin_count = 0;

	hlock->pin_count = pin_count;



	if (check && !mark_irqflags(curr, hlock))

		return 0;
@@ -3343,7 +3343,7 @@ __lock_set_class(struct lockdep_map *lock, const char *name, 
			hlock_class(hlock)->subclass, hlock->trylock,

				hlock->read, hlock->check, hlock->hardirqs_off,

				hlock->nest_lock, hlock->acquire_ip,

				hlock->references))

				hlock->references, hlock->pin_count))

			return 0;

	}
@@ -3433,7 +3433,7 @@ __lock_release(struct lockdep_map *lock, int nested, unsigned long ip) 
			hlock_class(hlock)->subclass, hlock->trylock,

				hlock->read, hlock->check, hlock->hardirqs_off,

				hlock->nest_lock, hlock->acquire_ip,

				hlock->references))

				hlock->references, hlock->pin_count))

			return 0;

	}
@@ -3583,7 +3583,7 @@ void lock_acquire(struct lockdep_map *lock, unsigned int subclass, 
	current->lockdep_recursion = 1;

	trace_lock_acquire(lock, subclass, trylock, read, check, nest_lock, ip);

	__lock_acquire(lock, subclass, trylock, read, check,

		       irqs_disabled_flags(flags), nest_lock, ip, 0);

		       irqs_disabled_flags(flags), nest_lock, ip, 0, 0);

	current->lockdep_recursion = 0;

	raw_local_irq_restore(flags);

}