Commit bff1b208 authored by Steven Rostedt (VMware)'s avatar Steven Rostedt (VMware)
Browse files

tracing: Partial revert of "tracing: Centralize preemptirq tracepoints and unify their usage" 

Joel Fernandes created a nice patch that cleaned up the duplicate hooks used
by lockdep and irqsoff latency tracer. It made both use tracepoints. But it
caused lockdep to trigger several false positives. We have not figured out
why yet, but removing lockdep from using the trace event hooks and just call
its helper functions directly (like it use to), makes the problem go away.

This is a partial revert of the clean up patch c3bc8fd6 ("tracing:
Centralize preemptirq tracepoints and unify their usage") that adds direct
calls for lockdep, but also keeps most of the clean up done to get rid of
the horrible preprocessor if statements.

Link: http://lkml.kernel.org/r/20180806155058.5ee875f4@gandalf.local.home



Cc: Peter Zijlstra <peterz@infradead.org>
Reviewed-by: default avatarJoel Fernandes (Google) <joel@joelfernandes.org>
Fixes: c3bc8fd6 ("tracing: Centralize preemptirq tracepoints and unify their usage")
Signed-off-by: default avatarSteven Rostedt (VMware) <rostedt@goodmis.org>
parent da5b3ebb

include/linux/irqflags.h

+6 −2
Original line number Diff line number Diff line
@@ -19,9 +19,13 @@ 
#ifdef CONFIG_PROVE_LOCKING

  extern void trace_softirqs_on(unsigned long ip);

  extern void trace_softirqs_off(unsigned long ip);

  extern void lockdep_hardirqs_on(unsigned long ip);

  extern void lockdep_hardirqs_off(unsigned long ip);

#else

# define trace_softirqs_on(ip)	do { } while (0)

# define trace_softirqs_off(ip)	do { } while (0)

  static inline void trace_softirqs_on(unsigned long ip) { }

  static inline void trace_softirqs_off(unsigned long ip) { }

  static inline void lockdep_hardirqs_on(unsigned long ip) { }

  static inline void lockdep_hardirqs_off(unsigned long ip) { }

#endif



#ifdef CONFIG_TRACE_IRQFLAGS

include/linux/lockdep.h

+0 −2
Original line number Diff line number Diff line
@@ -267,7 +267,6 @@ struct held_lock { 
 * Initialization, self-test and debugging-output methods:

 */

extern void lockdep_init(void);

extern void lockdep_init_early(void);

extern void lockdep_reset(void);

extern void lockdep_reset_lock(struct lockdep_map *lock);

extern void lockdep_free_key_range(void *start, unsigned long size);
@@ -408,7 +407,6 @@ static inline void lockdep_on(void) 
# define lock_set_class(l, n, k, s, i)		do { } while (0)

# define lock_set_subclass(l, s, i)		do { } while (0)

# define lockdep_init()				do { } while (0)

# define lockdep_init_early()			do { } while (0)

# define lockdep_init_map(lock, name, key, sub) \

		do { (void)(name); (void)(key); } while (0)

# define lockdep_set_class(lock, key)		do { (void)(key); } while (0)

init/main.c

+0 −2
Original line number Diff line number Diff line
@@ -649,8 +649,6 @@ asmlinkage __visible void __init start_kernel(void) 
	call_function_init();

	WARN(!irqs_disabled(), "Interrupts were enabled early\n");



	lockdep_init_early();



	early_boot_irqs_disabled = false;

	local_irq_enable();

kernel/locking/lockdep.c

+2 −12
Original line number Diff line number Diff line
@@ -2840,8 +2840,7 @@ static void __trace_hardirqs_on_caller(unsigned long ip) 
	debug_atomic_inc(hardirqs_on_events);

}



static void lockdep_hardirqs_on(void *none, unsigned long ignore,

				unsigned long ip)

void lockdep_hardirqs_on(unsigned long ip)

{

	if (unlikely(!debug_locks || current->lockdep_recursion))

		return;
@@ -2885,8 +2884,7 @@ static void lockdep_hardirqs_on(void *none, unsigned long ignore, 
/*

 * Hardirqs were disabled:

 */

static void lockdep_hardirqs_off(void *none, unsigned long ignore,

				 unsigned long ip)

void lockdep_hardirqs_off(unsigned long ip)

{

	struct task_struct *curr = current;
@@ -4315,14 +4313,6 @@ out_restore: 
	raw_local_irq_restore(flags);

}



void __init lockdep_init_early(void)

{

#ifdef CONFIG_PROVE_LOCKING

	register_trace_prio_irq_disable(lockdep_hardirqs_off, NULL, INT_MAX);

	register_trace_prio_irq_enable(lockdep_hardirqs_on, NULL, INT_MIN);

#endif

}



void __init lockdep_init(void)

{

	printk("Lock dependency validator: Copyright (c) 2006 Red Hat, Inc., Ingo Molnar\n");

kernel/trace/trace_preemptirq.c

+20 −16
Original line number Diff line number Diff line
@@ -19,42 +19,46 @@ static DEFINE_PER_CPU(int, tracing_irq_cpu); 


void trace_hardirqs_on(void)

{

	if (!this_cpu_read(tracing_irq_cpu))

		return;



	if (this_cpu_read(tracing_irq_cpu)) {

		trace_irq_enable_rcuidle(CALLER_ADDR0, CALLER_ADDR1);

		this_cpu_write(tracing_irq_cpu, 0);

	}



	lockdep_hardirqs_on(CALLER_ADDR0);

}

EXPORT_SYMBOL(trace_hardirqs_on);



void trace_hardirqs_off(void)

{

	if (this_cpu_read(tracing_irq_cpu))

		return;



	if (!this_cpu_read(tracing_irq_cpu)) {

		this_cpu_write(tracing_irq_cpu, 1);

		trace_irq_disable_rcuidle(CALLER_ADDR0, CALLER_ADDR1);

	}



	lockdep_hardirqs_off(CALLER_ADDR0);

}

EXPORT_SYMBOL(trace_hardirqs_off);



__visible void trace_hardirqs_on_caller(unsigned long caller_addr)

{

	if (!this_cpu_read(tracing_irq_cpu))

		return;



	if (this_cpu_read(tracing_irq_cpu)) {

		trace_irq_enable_rcuidle(CALLER_ADDR0, caller_addr);

		this_cpu_write(tracing_irq_cpu, 0);

	}



	lockdep_hardirqs_on(CALLER_ADDR0);

}

EXPORT_SYMBOL(trace_hardirqs_on_caller);



__visible void trace_hardirqs_off_caller(unsigned long caller_addr)

{

	if (this_cpu_read(tracing_irq_cpu))

		return;



	if (!this_cpu_read(tracing_irq_cpu)) {

		this_cpu_write(tracing_irq_cpu, 1);

		trace_irq_disable_rcuidle(CALLER_ADDR0, caller_addr);

	}



	lockdep_hardirqs_off(CALLER_ADDR0);

}

EXPORT_SYMBOL(trace_hardirqs_off_caller);

#endif /* CONFIG_TRACE_IRQFLAGS */

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