forked from luck/tmp_suning_uos_patched
perf/core: Fix event_function_local()
Vincent reported triggering the WARN_ON_ONCE() in event_function_local().
While thinking through cases I noticed that by using event_function()
directly, we miss the inactive case usually handled by
event_function_call().
Therefore construct a blend of event_function_call() and
event_function() that handles the cases relevant to
event_function_local().
Reported-by: Vince Weaver <vincent.weaver@maine.edu>
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: stable@vger.kernel.org # 4.5+
Fixes: fae3fde651
("perf: Collapse and fix event_function_call() users")
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
parent
6c4687cc17
commit
cca2094605
@ -242,18 +242,6 @@ static int event_function(void *info)
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return ret;
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}
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static void event_function_local(struct perf_event *event, event_f func, void *data)
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{
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struct event_function_struct efs = {
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.event = event,
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.func = func,
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.data = data,
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};
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int ret = event_function(&efs);
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WARN_ON_ONCE(ret);
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}
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static void event_function_call(struct perf_event *event, event_f func, void *data)
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{
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struct perf_event_context *ctx = event->ctx;
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@ -303,6 +291,54 @@ static void event_function_call(struct perf_event *event, event_f func, void *da
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raw_spin_unlock_irq(&ctx->lock);
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}
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/*
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* Similar to event_function_call() + event_function(), but hard assumes IRQs
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* are already disabled and we're on the right CPU.
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*/
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static void event_function_local(struct perf_event *event, event_f func, void *data)
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{
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struct perf_event_context *ctx = event->ctx;
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struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
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struct task_struct *task = READ_ONCE(ctx->task);
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struct perf_event_context *task_ctx = NULL;
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WARN_ON_ONCE(!irqs_disabled());
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if (task) {
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if (task == TASK_TOMBSTONE)
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return;
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task_ctx = ctx;
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}
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perf_ctx_lock(cpuctx, task_ctx);
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task = ctx->task;
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if (task == TASK_TOMBSTONE)
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goto unlock;
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if (task) {
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/*
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* We must be either inactive or active and the right task,
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* otherwise we're screwed, since we cannot IPI to somewhere
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* else.
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*/
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if (ctx->is_active) {
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if (WARN_ON_ONCE(task != current))
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goto unlock;
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if (WARN_ON_ONCE(cpuctx->task_ctx != ctx))
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goto unlock;
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}
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} else {
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WARN_ON_ONCE(&cpuctx->ctx != ctx);
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}
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func(event, cpuctx, ctx, data);
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unlock:
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perf_ctx_unlock(cpuctx, task_ctx);
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}
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#define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\
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PERF_FLAG_FD_OUTPUT |\
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PERF_FLAG_PID_CGROUP |\
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