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Commit 65ab504d authored by Prateek Sood's avatar Prateek Sood Committed by Gerrit - the friendly Code Review server
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lockdep: save caller1 for locks in task_struct 



Currently lockdep saves caller0 for locking API's in
task_struct. Save caller1 also for a task acquiring the
lock. This is helpful for locks like cpu_hotplug_lock
which is acquired/release inside a helper function like
cpus_read_lock(). Caller1 shall help in getting caller of
cpus_read_lock().

Change-Id: I3ea30990245f478778c2e58348a84ab40610056d
Signed-off-by: default avatarPrateek Sood <prsood@codeaurora.org>
parent 4d10f167

include/linux/lockdep.h

+2 −0
Original line number Diff line number Diff line
@@ -157,6 +157,7 @@ struct lockdep_map { 
#ifdef CONFIG_LOCK_STAT

	int				cpu;

	unsigned long			ip;

	unsigned long			ip_caller;

#endif

};
@@ -233,6 +234,7 @@ struct held_lock { 
	 */

	u64				prev_chain_key;

	unsigned long			acquire_ip;

	unsigned long			acquire_ip_caller;

	struct lockdep_map		*instance;

	struct lockdep_map		*nest_lock;

#ifdef CONFIG_LOCK_STAT

kernel/locking/lockdep.c

+41 −3
Original line number Diff line number Diff line
@@ -52,6 +52,7 @@ 
#include <linux/nmi.h>



#include <asm/sections.h>

#include <asm/stacktrace.h>



#include "lockdep_internals.h"
@@ -72,6 +73,8 @@ module_param(lock_stat, int, 0644); 
#define lock_stat 0

#endif



#define MAX_ITR 20



/*

 * lockdep_lock: protects the lockdep graph, the hashes and the

 *               class/list/hash allocators.
@@ -3259,6 +3262,33 @@ print_lock_nested_lock_not_held(struct task_struct *curr, 


static int __lock_is_held(const struct lockdep_map *lock, int read);



static unsigned long lockdep_walk_stack(unsigned long addr)

{

	int ret;

	struct stackframe frame;

	struct task_struct *tsk = current;

	bool end_search = false;

	int counter = 0;



	frame.fp = (unsigned long)__builtin_frame_address(0);

	frame.pc = (unsigned long)lockdep_walk_stack;



	while (counter < MAX_ITR) {

		counter++;

		if (frame.pc == addr)

			end_search = true;



		ret = unwind_frame(tsk, &frame);

		if ((ret < 0) || end_search)

			break;

	}



	if (unlikely(ret < 0) || unlikely(counter == MAX_ITR))

		return 0;

	else

		return frame.pc;

}



/*

 * This gets called for every mutex_lock*()/spin_lock*() operation.

 * We maintain the dependency maps and validate the locking attempt:
@@ -3266,7 +3296,8 @@ static int __lock_is_held(const struct lockdep_map *lock, int read); 
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 pin_count)

			  int references, int pin_count,

			  unsigned long ip_caller)

{

	struct task_struct *curr = current;

	struct lock_class *class = NULL;
@@ -3364,6 +3395,10 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass, 
	hlock->holdtime_stamp = lockstat_clock();

#endif

	hlock->pin_count = pin_count;

	if (!ip_caller)

		hlock->acquire_ip_caller = lockdep_walk_stack(ip);

	else

		hlock->acquire_ip_caller = ip_caller;



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

		return 0;
@@ -3550,7 +3585,8 @@ static int reacquire_held_locks(struct task_struct *curr, unsigned int depth, 
				    hlock->read, hlock->check,

				    hlock->hardirqs_off,

				    hlock->nest_lock, hlock->acquire_ip,

				    hlock->references, hlock->pin_count))

				    hlock->references, hlock->pin_count,

				    hlock->acquire_ip_caller))

			return 1;

	}

	return 0;
@@ -3626,6 +3662,7 @@ static int __lock_downgrade(struct lockdep_map *lock, unsigned long ip) 
	WARN(hlock->read, "downgrading a read lock");

	hlock->read = 1;

	hlock->acquire_ip = ip;

	hlock->acquire_ip_caller = lockdep_walk_stack(ip);



	if (reacquire_held_locks(curr, depth, i))

		return 0;
@@ -3901,7 +3938,7 @@ 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, 0);

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

	current->lockdep_recursion = 0;

	raw_local_irq_restore(flags);

}
@@ -4119,6 +4156,7 @@ __lock_acquired(struct lockdep_map *lock, unsigned long ip) 


	lock->cpu = cpu;

	lock->ip = ip;

	lock->ip_caller = lockdep_walk_stack(ip);

}



void lock_contended(struct lockdep_map *lock, unsigned long ip)