From c994d6136738fd8b24a79f5ad8df40a6a79e2cf7 Mon Sep 17 00:00:00 2001
From: Peter Zijlstra <peterz@infradead.org>
Date: Fri, 8 Jan 2016 09:20:23 +0100
Subject: [PATCH] perf: Add lockdep assertions

Make various bugs easier to see.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.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>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 kernel/events/core.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/kernel/events/core.c b/kernel/events/core.c
index bf8244190d0f..c77b05d9a37d 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -1246,6 +1246,8 @@ ctx_group_list(struct perf_event *event, struct perf_event_context *ctx)
 static void
 list_add_event(struct perf_event *event, struct perf_event_context *ctx)
 {
+	lockdep_assert_held(&ctx->lock);
+
 	WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
 	event->attach_state |= PERF_ATTACH_CONTEXT;
 
@@ -2342,8 +2344,10 @@ static void ctx_sched_out(struct perf_event_context *ctx,
 			  struct perf_cpu_context *cpuctx,
 			  enum event_type_t event_type)
 {
-	struct perf_event *event;
 	int is_active = ctx->is_active;
+	struct perf_event *event;
+
+	lockdep_assert_held(&ctx->lock);
 
 	ctx->is_active &= ~event_type;
 	if (likely(!ctx->nr_events))
@@ -2725,8 +2729,10 @@ ctx_sched_in(struct perf_event_context *ctx,
 	     enum event_type_t event_type,
 	     struct task_struct *task)
 {
-	u64 now;
 	int is_active = ctx->is_active;
+	u64 now;
+
+	lockdep_assert_held(&ctx->lock);
 
 	ctx->is_active |= event_type;
 	if (likely(!ctx->nr_events))
-- 
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