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Commit 51676957 authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

perf: Fix duplicate events with multiple-pmu vs software events 



Because the multi-pmu bits can share contexts between struct pmu
instances we could get duplicate events by iterating the pmu list.

Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
LKML-Reference: <new-submission>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 6313e3c2

include/linux/perf_event.h

+1 −0
Original line number Original line Diff line number Diff line
@@ -887,6 +887,7 @@ struct perf_cpu_context { 
	int				exclusive;

	int				exclusive;

	struct list_head		rotation_list;

	struct list_head		rotation_list;

	int				jiffies_interval;

	int				jiffies_interval;

	struct pmu			*active_pmu;

};

};





struct perf_output_handle {

struct perf_output_handle {

kernel/perf_event.c

+29 −6
Original line number Original line Diff line number Diff line
@@ -3824,6 +3824,8 @@ static void perf_event_task_event(struct perf_task_event *task_event) 
	rcu_read_lock();

	rcu_read_lock();

	list_for_each_entry_rcu(pmu, &pmus, entry) {

	list_for_each_entry_rcu(pmu, &pmus, entry) {

		cpuctx = get_cpu_ptr(pmu->pmu_cpu_context);

		cpuctx = get_cpu_ptr(pmu->pmu_cpu_context);

		if (cpuctx->active_pmu != pmu)

			goto next;

		perf_event_task_ctx(&cpuctx->ctx, task_event);

		perf_event_task_ctx(&cpuctx->ctx, task_event);





		ctx = task_event->task_ctx;

		ctx = task_event->task_ctx;
@@ -3959,6 +3961,8 @@ static void perf_event_comm_event(struct perf_comm_event *comm_event) 
	rcu_read_lock();

	rcu_read_lock();

	list_for_each_entry_rcu(pmu, &pmus, entry) {

	list_for_each_entry_rcu(pmu, &pmus, entry) {

		cpuctx = get_cpu_ptr(pmu->pmu_cpu_context);

		cpuctx = get_cpu_ptr(pmu->pmu_cpu_context);

		if (cpuctx->active_pmu != pmu)

			goto next;

		perf_event_comm_ctx(&cpuctx->ctx, comm_event);

		perf_event_comm_ctx(&cpuctx->ctx, comm_event);





		ctxn = pmu->task_ctx_nr;

		ctxn = pmu->task_ctx_nr;
@@ -4144,6 +4148,8 @@ got_name: 
	rcu_read_lock();

	rcu_read_lock();

	list_for_each_entry_rcu(pmu, &pmus, entry) {

	list_for_each_entry_rcu(pmu, &pmus, entry) {

		cpuctx = get_cpu_ptr(pmu->pmu_cpu_context);

		cpuctx = get_cpu_ptr(pmu->pmu_cpu_context);

		if (cpuctx->active_pmu != pmu)

			goto next;

		perf_event_mmap_ctx(&cpuctx->ctx, mmap_event,

		perf_event_mmap_ctx(&cpuctx->ctx, mmap_event,

					vma->vm_flags & VM_EXEC);

					vma->vm_flags & VM_EXEC);
@@ -5145,20 +5151,36 @@ static void *find_pmu_context(int ctxn) 
	return NULL;

	return NULL;

}

}





static void free_pmu_context(void * __percpu cpu_context)

static void update_pmu_context(struct pmu *pmu, struct pmu *old_pmu)

{

{

	struct pmu *pmu;

	int cpu;



	for_each_possible_cpu(cpu) {

		struct perf_cpu_context *cpuctx;



		cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);



		if (cpuctx->active_pmu == old_pmu)

			cpuctx->active_pmu = pmu;

	}

}



static void free_pmu_context(struct pmu *pmu)

{

	struct pmu *i;





	mutex_lock(&pmus_lock);

	mutex_lock(&pmus_lock);

	/*

	/*

	 * Like a real lame refcount.

	 * Like a real lame refcount.

	 */

	 */

	list_for_each_entry(pmu, &pmus, entry) {

	list_for_each_entry(i, &pmus, entry) {

		if (pmu->pmu_cpu_context == cpu_context)

		if (i->pmu_cpu_context == pmu->pmu_cpu_context) {

			update_pmu_context(i, pmu);

			goto out;

			goto out;

		}

		}

	}





	free_percpu(cpu_context);

	free_percpu(pmu->pmu_cpu_context);

out:

out:

	mutex_unlock(&pmus_lock);

	mutex_unlock(&pmus_lock);

}

}
@@ -5190,6 +5212,7 @@ int perf_pmu_register(struct pmu *pmu) 
		cpuctx->ctx.pmu = pmu;

		cpuctx->ctx.pmu = pmu;

		cpuctx->jiffies_interval = 1;

		cpuctx->jiffies_interval = 1;

		INIT_LIST_HEAD(&cpuctx->rotation_list);

		INIT_LIST_HEAD(&cpuctx->rotation_list);

		cpuctx->active_pmu = pmu;

	}

	}





got_cpu_context:

got_cpu_context:
@@ -5241,7 +5264,7 @@ void perf_pmu_unregister(struct pmu *pmu) 
	synchronize_rcu();

	synchronize_rcu();





	free_percpu(pmu->pmu_disable_count);

	free_percpu(pmu->pmu_disable_count);

	free_pmu_context(pmu->pmu_cpu_context);

	free_pmu_context(pmu);

}

}





struct pmu *perf_init_event(struct perf_event *event)

struct pmu *perf_init_event(struct perf_event *event)