perf symbols: Fix multiple initialization of symbol system

By returning immediately if it was already initialized, do it as well at
symbol__exit, refusing multiple deinitializations.

This fixes problems in the kmem, sched and timechart commands.

Reported-by: Davidlohr Bueso <dave@gnu.org>
Cc: Davidlohr Bueso <dave@gnu.org>
Signed-off-by: Jovi Zhang <bookjovi@gmail.com>
LKML-Reference: AANLkTi=9Cn=R8SPMCRp5z+gEjXbaBHeb-AaOtRbuwwcn@mail.gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/symbol.c

@@ -2268,6 +2268,9 @@ static int setup_list(struct strlist **list, const char *list_str,
 
 int symbol__init(void)
 {
+	if (symbol_conf.initialized)
+		return 0;
+
 	elf_version(EV_CURRENT);
 	if (symbol_conf.sort_by_name)
 		symbol_conf.priv_size += (sizeof(struct symbol_name_rb_node) -
@@ -2293,6 +2296,7 @@ int symbol__init(void)
 		       symbol_conf.sym_list_str, "symbol") < 0)
 		goto out_free_comm_list;
 
+	symbol_conf.initialized = true;
 	return 0;
 
 out_free_dso_list:
@@ -2304,11 +2308,14 @@ int symbol__init(void)
 
 void symbol__exit(void)
 {
+	if (!symbol_conf.initialized)
+		return;
 	strlist__delete(symbol_conf.sym_list);
 	strlist__delete(symbol_conf.dso_list);
 	strlist__delete(symbol_conf.comm_list);
 	vmlinux_path__exit();
 	symbol_conf.sym_list = symbol_conf.dso_list = symbol_conf.comm_list = NULL;
+	symbol_conf.initialized = false;
 }
 
 int machines__create_kernel_maps(struct rb_root *self, pid_t pid)

tools/perf/util/symbol.h

@@ -69,7 +69,8 @@ struct symbol_conf {
 			show_nr_samples,
 			use_callchain,
 			exclude_other,
-			show_cpu_utilization;
+			show_cpu_utilization,
+			initialized;
 	const char	*vmlinux_name,
 			*source_prefix,
 			*field_sep;