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

Pull perf fixes from Ingo Molnar:
 "Two core subsystem fixes, plus a handful of tooling fixes"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf: Fix race in swevent hash
  perf: Fix race in perf_event_exec()
  perf list: Robustify event printing routine
  perf list: Add support for PERF_COUNT_SW_BPF_OUT
  perf hists browser: Fix segfault if use symbol filter in cmdline
  perf hists browser: Reset selection when refresh
  perf hists browser: Add NULL pointer check to prevent crash
  perf buildid-list: Fix return value of perf buildid-list -k
  perf buildid-list: Show running kernel build id fix

kernel/events/core.c

@@ -3154,15 +3154,16 @@ static int event_enable_on_exec(struct perf_event *event,
  * Enable all of a task's events that have been marked enable-on-exec.
  * This expects task == current.
  */
-static void perf_event_enable_on_exec(struct perf_event_context *ctx)
+static void perf_event_enable_on_exec(int ctxn)
 {
-	struct perf_event_context *clone_ctx = NULL;
+	struct perf_event_context *ctx, *clone_ctx = NULL;
 	struct perf_event *event;
 	unsigned long flags;
 	int enabled = 0;
 	int ret;
 
 	local_irq_save(flags);
+	ctx = current->perf_event_ctxp[ctxn];
 	if (!ctx || !ctx->nr_events)
 		goto out;
 
@@ -3205,17 +3206,11 @@ static void perf_event_enable_on_exec(struct perf_event_context *ctx)
 
 void perf_event_exec(void)
 {
-	struct perf_event_context *ctx;
 	int ctxn;
 
 	rcu_read_lock();
-	for_each_task_context_nr(ctxn) {
-		ctx = current->perf_event_ctxp[ctxn];
-		if (!ctx)
-			continue;
-
-		perf_event_enable_on_exec(ctx);
-	}
+	for_each_task_context_nr(ctxn)
+		perf_event_enable_on_exec(ctxn);
 	rcu_read_unlock();
 }
 
@@ -6493,9 +6488,6 @@ struct swevent_htable {
 
 	/* Recursion avoidance in each contexts */
 	int				recursion[PERF_NR_CONTEXTS];
-
-	/* Keeps track of cpu being initialized/exited */
-	bool				online;
 };
 
 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
@@ -6753,14 +6745,8 @@ static int perf_swevent_add(struct perf_event *event, int flags)
 	hwc->state = !(flags & PERF_EF_START);
 
 	head = find_swevent_head(swhash, event);
-	if (!head) {
-		/*
-		 * We can race with cpu hotplug code. Do not
-		 * WARN if the cpu just got unplugged.
-		 */
-		WARN_ON_ONCE(swhash->online);
+	if (WARN_ON_ONCE(!head))
 		return -EINVAL;
-	}
 
 	hlist_add_head_rcu(&event->hlist_entry, head);
 	perf_event_update_userpage(event);
@@ -6828,7 +6814,6 @@ static int swevent_hlist_get_cpu(struct perf_event *event, int cpu)
 	int err = 0;
 
 	mutex_lock(&swhash->hlist_mutex);
-
 	if (!swevent_hlist_deref(swhash) && cpu_online(cpu)) {
 		struct swevent_hlist *hlist;
 
@@ -9291,7 +9276,6 @@ static void perf_event_init_cpu(int cpu)
 	struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
 
 	mutex_lock(&swhash->hlist_mutex);
-	swhash->online = true;
 	if (swhash->hlist_refcount > 0) {
 		struct swevent_hlist *hlist;
 
@@ -9333,14 +9317,7 @@ static void perf_event_exit_cpu_context(int cpu)
 
 static void perf_event_exit_cpu(int cpu)
 {
-	struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
-
 	perf_event_exit_cpu_context(cpu);
-
-	mutex_lock(&swhash->hlist_mutex);
-	swhash->online = false;
-	swevent_hlist_release(swhash);
-	mutex_unlock(&swhash->hlist_mutex);
 }
 #else
 static inline void perf_event_exit_cpu(int cpu) { }

tools/perf/builtin-buildid-list.c

@@ -110,7 +110,7 @@ int cmd_buildid_list(int argc, const char **argv,
 	setup_pager();
 
 	if (show_kernel)
-		return sysfs__fprintf_build_id(stdout);
+		return !(sysfs__fprintf_build_id(stdout) > 0);
 
 	return perf_session__list_build_ids(force, with_hits);
 }

tools/perf/ui/browsers/hists.c

@@ -298,6 +298,9 @@ static bool hist_browser__toggle_fold(struct hist_browser *browser)
 	struct callchain_list *cl = container_of(ms, struct callchain_list, ms);
 	bool has_children;
 
+	if (!he || !ms)
+		return false;
+
 	if (ms == &he->ms)
 		has_children = hist_entry__toggle_fold(he);
 	else
@@ -928,6 +931,8 @@ static unsigned int hist_browser__refresh(struct ui_browser *browser)
 	}
 
 	ui_browser__hists_init_top(browser);
+	hb->he_selection = NULL;
+	hb->selection = NULL;
 
 	for (nd = browser->top; nd; nd = rb_next(nd)) {
 		struct hist_entry *h = rb_entry(nd, struct hist_entry, rb_node);
@@ -1033,6 +1038,9 @@ static void ui_browser__hists_seek(struct ui_browser *browser,
 	 * and stop when we printed enough lines to fill the screen.
 	 */
 do_offset:
+	if (!nd)
+		return;
+
 	if (offset > 0) {
 		do {
 			h = rb_entry(nd, struct hist_entry, rb_node);

tools/perf/util/build-id.c

@@ -91,7 +91,7 @@ int build_id__sprintf(const u8 *build_id, int len, char *bf)
 		bid += 2;
 	}
 
-	return raw - build_id;
+	return (bid - bf) + 1;
 }
 
 int sysfs__sprintf_build_id(const char *root_dir, char *sbuild_id)

tools/perf/util/parse-events.c

@@ -124,6 +124,10 @@ struct event_symbol event_symbols_sw[PERF_COUNT_SW_MAX] = {
 		.symbol = "dummy",
 		.alias  = "",
 	},
+	[PERF_COUNT_SW_BPF_OUTPUT] = {
+		.symbol = "bpf-output",
+		.alias  = "",
+	},
 };
 
 #define __PERF_EVENT_FIELD(config, name) \
@@ -1879,7 +1883,7 @@ void print_symbol_events(const char *event_glob, unsigned type,
 
 	for (i = 0; i < max; i++, syms++) {
 
-		if (event_glob != NULL &&
+		if (event_glob != NULL && syms->symbol != NULL &&
 		    !(strglobmatch(syms->symbol, event_glob) ||
 		      (syms->alias && strglobmatch(syms->alias, event_glob))))
 			continue;