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| author | Peter Zijlstra <a.p.zijlstra@chello.nl> | 2010-09-13 13:06:55 +0400 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2010-09-13 19:08:42 +0400 |
| commit | cde8e88498c8de69271fcb6d4dd974979368fa67 (patch) | |
| tree | 34eb745cc6f3e5a5dbe0918f4920424be70bcfff | |
| parent | b0b2072df3b544f56b90173c2cde7a374c51546b (diff) | |
| download | linux-cde8e88498c8de69271fcb6d4dd974979368fa67.tar.xz | |
perf: Sanitize the RCU logic
Simplify things and simply synchronize against two RCU variants for
PMU unregister -- we don't care about performance, its module unload
if anything.
Reported-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
| -rw-r--r-- | kernel/perf_event.c | 17 |
1 files changed, 9 insertions, 8 deletions
diff --git a/kernel/perf_event.c b/kernel/perf_event.c index f29b52576ec1..bc46bff69620 100644 --- a/kernel/perf_event.c +++ b/kernel/perf_event.c @@ -3810,7 +3810,7 @@ static void perf_event_task_event(struct perf_task_event *task_event) struct pmu *pmu; int ctxn; - rcu_read_lock_sched(); + rcu_read_lock(); list_for_each_entry_rcu(pmu, &pmus, entry) { cpuctx = this_cpu_ptr(pmu->pmu_cpu_context); perf_event_task_ctx(&cpuctx->ctx, task_event); @@ -3825,7 +3825,7 @@ static void perf_event_task_event(struct perf_task_event *task_event) if (ctx) perf_event_task_ctx(ctx, task_event); } - rcu_read_unlock_sched(); + rcu_read_unlock(); } static void perf_event_task(struct task_struct *task, @@ -3943,7 +3943,7 @@ static void perf_event_comm_event(struct perf_comm_event *comm_event) comm_event->event_id.header.size = sizeof(comm_event->event_id) + size; - rcu_read_lock_sched(); + rcu_read_lock(); list_for_each_entry_rcu(pmu, &pmus, entry) { cpuctx = this_cpu_ptr(pmu->pmu_cpu_context); perf_event_comm_ctx(&cpuctx->ctx, comm_event); @@ -3956,7 +3956,7 @@ static void perf_event_comm_event(struct perf_comm_event *comm_event) if (ctx) perf_event_comm_ctx(ctx, comm_event); } - rcu_read_unlock_sched(); + rcu_read_unlock(); } void perf_event_comm(struct task_struct *task) @@ -4126,7 +4126,7 @@ got_name: mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size; - rcu_read_lock_sched(); + rcu_read_lock(); list_for_each_entry_rcu(pmu, &pmus, entry) { cpuctx = this_cpu_ptr(pmu->pmu_cpu_context); perf_event_mmap_ctx(&cpuctx->ctx, mmap_event, @@ -4142,7 +4142,7 @@ got_name: vma->vm_flags & VM_EXEC); } } - rcu_read_unlock_sched(); + rcu_read_unlock(); kfree(buf); } @@ -5218,10 +5218,11 @@ void perf_pmu_unregister(struct pmu *pmu) mutex_unlock(&pmus_lock); /* - * We use the pmu list either under SRCU or preempt_disable, - * synchronize_srcu() implies synchronize_sched() so we're good. + * We dereference the pmu list under both SRCU and regular RCU, so + * synchronize against both of those. */ synchronize_srcu(&pmus_srcu); + synchronize_rcu(); free_percpu(pmu->pmu_disable_count); free_pmu_context(pmu->pmu_cpu_context); |