From 5167695753c63444a9e6cbbef136200a16c7a225 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Tue, 7 Dec 2010 14:18:20 +0100 Subject: [PATCH] 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: Peter Zijlstra Signed-off-by: Thomas Gleixner LKML-Reference: Signed-off-by: Ingo Molnar --- include/linux/perf_event.h | 1 + kernel/perf_event.c | 35 +++++++++++++++++++++++++++++------ 2 files changed, 30 insertions(+), 6 deletions(-) diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index de2c41758e29e2..4f1279e105ee14 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -887,6 +887,7 @@ struct perf_cpu_context { int exclusive; struct list_head rotation_list; int jiffies_interval; + struct pmu *active_pmu; }; struct perf_output_handle { diff --git a/kernel/perf_event.c b/kernel/perf_event.c index eac7e3364335a7..7b870174c56d24 100644 --- a/kernel/perf_event.c +++ b/kernel/perf_event.c @@ -3824,6 +3824,8 @@ static void perf_event_task_event(struct perf_task_event *task_event) rcu_read_lock(); list_for_each_entry_rcu(pmu, &pmus, entry) { cpuctx = get_cpu_ptr(pmu->pmu_cpu_context); + if (cpuctx->active_pmu != pmu) + goto next; perf_event_task_ctx(&cpuctx->ctx, task_event); ctx = task_event->task_ctx; @@ -3959,6 +3961,8 @@ static void perf_event_comm_event(struct perf_comm_event *comm_event) rcu_read_lock(); list_for_each_entry_rcu(pmu, &pmus, entry) { cpuctx = get_cpu_ptr(pmu->pmu_cpu_context); + if (cpuctx->active_pmu != pmu) + goto next; perf_event_comm_ctx(&cpuctx->ctx, comm_event); ctxn = pmu->task_ctx_nr; @@ -4144,6 +4148,8 @@ static void perf_event_mmap_event(struct perf_mmap_event *mmap_event) rcu_read_lock(); list_for_each_entry_rcu(pmu, &pmus, entry) { cpuctx = get_cpu_ptr(pmu->pmu_cpu_context); + if (cpuctx->active_pmu != pmu) + goto next; perf_event_mmap_ctx(&cpuctx->ctx, mmap_event, vma->vm_flags & VM_EXEC); @@ -5145,20 +5151,36 @@ static void *find_pmu_context(int ctxn) 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); /* * Like a real lame refcount. */ - list_for_each_entry(pmu, &pmus, entry) { - if (pmu->pmu_cpu_context == cpu_context) + list_for_each_entry(i, &pmus, entry) { + if (i->pmu_cpu_context == pmu->pmu_cpu_context) { + update_pmu_context(i, pmu); goto out; + } } - free_percpu(cpu_context); + free_percpu(pmu->pmu_cpu_context); out: mutex_unlock(&pmus_lock); } @@ -5190,6 +5212,7 @@ int perf_pmu_register(struct pmu *pmu) cpuctx->ctx.pmu = pmu; cpuctx->jiffies_interval = 1; INIT_LIST_HEAD(&cpuctx->rotation_list); + cpuctx->active_pmu = pmu; } got_cpu_context: @@ -5241,7 +5264,7 @@ void perf_pmu_unregister(struct pmu *pmu) synchronize_rcu(); 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)