Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull perf fixes from Ingo Molnar:
 "Mostly tooling fixes, plus two uncore-PMU fixes, an uprobes fix, a
  perf-cgroups fix and an AUX events fix"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/x86/intel/uncore: Add enable_box for client MSR uncore
  perf/x86/intel/uncore: Fix uncore num_counters
  uprobes/x86: Fix RIP-relative handling of EVEX-encoded instructions
  perf/core: Set cgroup in CPU contexts for new cgroup events
  perf/core: Fix sideband list-iteration vs. event ordering NULL pointer deference crash
  perf probe ppc64le: Fix probe location when using DWARF
  perf probe: Add function to post process kernel trace events
  tools: Sync cpufeatures headers with the kernel
  toops: Sync tools/include/uapi/linux/bpf.h with the kernel
  tools: Sync cpufeatures.h and vmx.h with the kernel
  perf probe: Support signedness casting
  perf stat: Avoid skew when reading events
  perf probe: Fix module name matching
  perf probe: Adjust map->reloc offset when finding kernel symbol from map
  perf hists: Trim libtraceevent trace_seq buffers
  perf script: Add 'bpf-output' field to usage message

1 files changed, 54 insertions, 23 deletions

diff --git a/kernel/events/core.c b/kernel/events/core.c
index a19550d80ab1..1903b8f3a705 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -843,6 +843,32 @@ perf_cgroup_mark_enabled(struct perf_event *event,
 		}
 	}
 }
+
+/*
+ * Update cpuctx->cgrp so that it is set when first cgroup event is added and
+ * cleared when last cgroup event is removed.
+ */
+static inline void
+list_update_cgroup_event(struct perf_event *event,
+			 struct perf_event_context *ctx, bool add)
+{
+	struct perf_cpu_context *cpuctx;
+
+	if (!is_cgroup_event(event))
+		return;
+
+	if (add && ctx->nr_cgroups++)
+		return;
+	else if (!add && --ctx->nr_cgroups)
+		return;
+	/*
+	 * Because cgroup events are always per-cpu events,
+	 * this will always be called from the right CPU.
+	 */
+	cpuctx = __get_cpu_context(ctx);
+	cpuctx->cgrp = add ? event->cgrp : NULL;
+}
+
 #else /* !CONFIG_CGROUP_PERF */
 
 static inline bool
@@ -920,6 +946,13 @@ perf_cgroup_mark_enabled(struct perf_event *event,
 			 struct perf_event_context *ctx)
 {
 }
+
+static inline void
+list_update_cgroup_event(struct perf_event *event,
+			 struct perf_event_context *ctx, bool add)
+{
+}
+
 #endif
 
 /*
@@ -1392,6 +1425,7 @@ 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);
@@ -1412,8 +1446,7 @@ list_add_event(struct perf_event *event, struct perf_event_context *ctx)
 		list_add_tail(&event->group_entry, list);
 	}
 
-	if (is_cgroup_event(event))
-		ctx->nr_cgroups++;
+	list_update_cgroup_event(event, ctx, true);
 
 	list_add_rcu(&event->event_entry, &ctx->event_list);
 	ctx->nr_events++;
@@ -1581,8 +1614,6 @@ static void perf_group_attach(struct perf_event *event)
 static void
 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
 {
-	struct perf_cpu_context *cpuctx;
-
 	WARN_ON_ONCE(event->ctx != ctx);
 	lockdep_assert_held(&ctx->lock);
 
@@ -1594,20 +1625,7 @@ list_del_event(struct perf_event *event, struct perf_event_context *ctx)
 
 	event->attach_state &= ~PERF_ATTACH_CONTEXT;
 
-	if (is_cgroup_event(event)) {
-		ctx->nr_cgroups--;
-		/*
-		 * Because cgroup events are always per-cpu events, this will
-		 * always be called from the right CPU.
-		 */
-		cpuctx = __get_cpu_context(ctx);
-		/*
-		 * If there are no more cgroup events then clear cgrp to avoid
-		 * stale pointer in update_cgrp_time_from_cpuctx().
-		 */
-		if (!ctx->nr_cgroups)
-			cpuctx->cgrp = NULL;
-	}
+	list_update_cgroup_event(event, ctx, false);
 
 	ctx->nr_events--;
 	if (event->attr.inherit_stat)
@@ -1716,8 +1734,8 @@ static inline int pmu_filter_match(struct perf_event *event)
 static inline int
 event_filter_match(struct perf_event *event)
 {
-	return (event->cpu == -1 || event->cpu == smp_processor_id())
-	    && perf_cgroup_match(event) && pmu_filter_match(event);
+	return (event->cpu == -1 || event->cpu == smp_processor_id()) &&
+	       perf_cgroup_match(event) && pmu_filter_match(event);
 }
 
 static void
@@ -1737,8 +1755,8 @@ event_sched_out(struct perf_event *event,
 	 * maintained, otherwise bogus information is return
 	 * via read() for time_enabled, time_running:
 	 */
-	if (event->state == PERF_EVENT_STATE_INACTIVE
-	    && !event_filter_match(event)) {
+	if (event->state == PERF_EVENT_STATE_INACTIVE &&
+	    !event_filter_match(event)) {
 		delta = tstamp - event->tstamp_stopped;
 		event->tstamp_running += delta;
 		event->tstamp_stopped = tstamp;
@@ -2236,10 +2254,15 @@ perf_install_in_context(struct perf_event_context *ctx,
 
 	lockdep_assert_held(&ctx->mutex);
 
-	event->ctx = ctx;
 	if (event->cpu != -1)
 		event->cpu = cpu;
 
+	/*
+	 * Ensures that if we can observe event->ctx, both the event and ctx
+	 * will be 'complete'. See perf_iterate_sb_cpu().
+	 */
+	smp_store_release(&event->ctx, ctx);
+
 	if (!task) {
 		cpu_function_call(cpu, __perf_install_in_context, event);
 		return;
@@ -5969,6 +5992,14 @@ static void perf_iterate_sb_cpu(perf_iterate_f output, void *data)
 	struct perf_event *event;
 
 	list_for_each_entry_rcu(event, &pel->list, sb_list) {
+		/*
+		 * Skip events that are not fully formed yet; ensure that
+		 * if we observe event->ctx, both event and ctx will be
+		 * complete enough. See perf_install_in_context().
+		 */
+		if (!smp_load_acquire(&event->ctx))
+			continue;
+
 		if (event->state < PERF_EVENT_STATE_INACTIVE)
 			continue;
 		if (!event_filter_match(event))