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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: Peter 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: 2e80a82a49 ("perf: Dynamic pmu types")
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Peter Zijlstra 2018-09-25 17:58:35 +02:00 committed by Ingo Molnar
parent 291d0e5d81
commit a9f9772114
1 changed files with 2 additions and 7 deletions
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9
kernel/events/core.c
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@ -9431,9 +9431,7 @@ static void free_pmu_context(struct pmu *pmu)
if (pmu->task_ctx_nr > perf_invalid_context)
return;
mutex_lock(&pmus_lock);
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)
{
int remove_device;
mutex_lock(&pmus_lock);
remove_device = pmu_bus_running;
list_del_rcu(&pmu->entry);
mutex_unlock(&pmus_lock);
/*
* 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);
if (pmu->type >= PERF_TYPE_MAX)
idr_remove(&pmu_idr, pmu->type);
if (remove_device) {
if (pmu_bus_running) {
if (pmu->nr_addr_filters)
device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);
device_del(pmu->dev);
put_device(pmu->dev);
}
free_pmu_context(pmu);
mutex_unlock(&pmus_lock);
}
EXPORT_SYMBOL_GPL(perf_pmu_unregister);