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Commit a9f97721 authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

perf/core: Fix perf_pmu_unregister() locking 



When we unregister a PMU, we fail to serialize the @pmu_idr properly.
Fix that by doing the entire thing under pmu_lock.

Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Fixes: 2e80a82a ("perf: Dynamic pmu types")
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 291d0e5d

kernel/events/core.c

+2 −7
Original line number Original line Diff line number Diff line
@@ -9431,9 +9431,7 @@ static void free_pmu_context(struct pmu *pmu) 
	if (pmu->task_ctx_nr > perf_invalid_context)

	if (pmu->task_ctx_nr > perf_invalid_context)

		return;

		return;





	mutex_lock(&pmus_lock);

	free_percpu(pmu->pmu_cpu_context);

	free_percpu(pmu->pmu_cpu_context);

	mutex_unlock(&pmus_lock);

}

}





/*

/*
@@ -9689,12 +9687,8 @@ EXPORT_SYMBOL_GPL(perf_pmu_register); 




void perf_pmu_unregister(struct pmu *pmu)

void perf_pmu_unregister(struct pmu *pmu)

{

{

	int remove_device;



	mutex_lock(&pmus_lock);

	mutex_lock(&pmus_lock);

	remove_device = pmu_bus_running;

	list_del_rcu(&pmu->entry);

	list_del_rcu(&pmu->entry);

	mutex_unlock(&pmus_lock);





	/*

	/*

	 * We dereference the pmu list under both SRCU and regular RCU, so

	 * We dereference the pmu list under both SRCU and regular RCU, so
@@ -9706,13 +9700,14 @@ void perf_pmu_unregister(struct pmu *pmu) 
	free_percpu(pmu->pmu_disable_count);

	free_percpu(pmu->pmu_disable_count);

	if (pmu->type >= PERF_TYPE_MAX)

	if (pmu->type >= PERF_TYPE_MAX)

		idr_remove(&pmu_idr, pmu->type);

		idr_remove(&pmu_idr, pmu->type);

	if (remove_device) {

	if (pmu_bus_running) {

		if (pmu->nr_addr_filters)

		if (pmu->nr_addr_filters)

			device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);

			device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);

		device_del(pmu->dev);

		device_del(pmu->dev);

		put_device(pmu->dev);

		put_device(pmu->dev);

	}

	}

	free_pmu_context(pmu);

	free_pmu_context(pmu);

	mutex_unlock(&pmus_lock);

}

}

EXPORT_SYMBOL_GPL(perf_pmu_unregister);

EXPORT_SYMBOL_GPL(perf_pmu_unregister);