diff --git a/tools/perf/arch/x86/util/event.c b/tools/perf/arch/x86/util/event.c
index 5741ffe47312..e65b7dbe27fb 100644
--- a/tools/perf/arch/x86/util/event.c
+++ b/tools/perf/arch/x86/util/event.c
@@ -14,66 +14,79 @@
 
 #if defined(__x86_64__)
 
+struct perf_event__synthesize_extra_kmaps_cb_args {
+	struct perf_tool *tool;
+	perf_event__handler_t process;
+	struct machine *machine;
+	union perf_event *event;
+};
+
+static int perf_event__synthesize_extra_kmaps_cb(struct map *map, void *data)
+{
+	struct perf_event__synthesize_extra_kmaps_cb_args *args = data;
+	union perf_event *event = args->event;
+	struct kmap *kmap;
+	size_t size;
+
+	if (!__map__is_extra_kernel_map(map))
+		return 0;
+
+	kmap = map__kmap(map);
+
+	size = sizeof(event->mmap) - sizeof(event->mmap.filename) +
+		      PERF_ALIGN(strlen(kmap->name) + 1, sizeof(u64)) +
+		      args->machine->id_hdr_size;
+
+	memset(event, 0, size);
+
+	event->mmap.header.type = PERF_RECORD_MMAP;
+
+	/*
+	 * kernel uses 0 for user space maps, see kernel/perf_event.c
+	 * __perf_event_mmap
+	 */
+	if (machine__is_host(args->machine))
+		event->header.misc = PERF_RECORD_MISC_KERNEL;
+	else
+		event->header.misc = PERF_RECORD_MISC_GUEST_KERNEL;
+
+	event->mmap.header.size = size;
+
+	event->mmap.start = map__start(map);
+	event->mmap.len   = map__size(map);
+	event->mmap.pgoff = map__pgoff(map);
+	event->mmap.pid   = args->machine->pid;
+
+	strlcpy(event->mmap.filename, kmap->name, PATH_MAX);
+
+	if (perf_tool__process_synth_event(args->tool, event, args->machine, args->process) != 0)
+		return -1;
+
+	return 0;
+}
+
 int perf_event__synthesize_extra_kmaps(struct perf_tool *tool,
 				       perf_event__handler_t process,
 				       struct machine *machine)
 {
-	int rc = 0;
-	struct map_rb_node *pos;
+	int rc;
 	struct maps *kmaps = machine__kernel_maps(machine);
-	union perf_event *event = zalloc(sizeof(event->mmap) +
-					 machine->id_hdr_size);
+	struct perf_event__synthesize_extra_kmaps_cb_args args = {
+		.tool = tool,
+		.process = process,
+		.machine = machine,
+		.event = zalloc(sizeof(args.event->mmap) + machine->id_hdr_size),
+	};
 
-	if (!event) {
+	if (!args.event) {
 		pr_debug("Not enough memory synthesizing mmap event "
 			 "for extra kernel maps\n");
 		return -1;
 	}
 
-	maps__for_each_entry(kmaps, pos) {
-		struct kmap *kmap;
-		size_t size;
-		struct map *map = pos->map;
+	rc = maps__for_each_map(kmaps, perf_event__synthesize_extra_kmaps_cb, &args);
 
-		if (!__map__is_extra_kernel_map(map))
-			continue;
-
-		kmap = map__kmap(map);
-
-		size = sizeof(event->mmap) - sizeof(event->mmap.filename) +
-		       PERF_ALIGN(strlen(kmap->name) + 1, sizeof(u64)) +
-		       machine->id_hdr_size;
-
-		memset(event, 0, size);
-
-		event->mmap.header.type = PERF_RECORD_MMAP;
-
-		/*
-		 * kernel uses 0 for user space maps, see kernel/perf_event.c
-		 * __perf_event_mmap
-		 */
-		if (machine__is_host(machine))
-			event->header.misc = PERF_RECORD_MISC_KERNEL;
-		else
-			event->header.misc = PERF_RECORD_MISC_GUEST_KERNEL;
-
-		event->mmap.header.size = size;
-
-		event->mmap.start = map__start(map);
-		event->mmap.len   = map__size(map);
-		event->mmap.pgoff = map__pgoff(map);
-		event->mmap.pid   = machine->pid;
-
-		strlcpy(event->mmap.filename, kmap->name, PATH_MAX);
-
-		if (perf_tool__process_synth_event(tool, event, machine,
-						   process) != 0) {
-			rc = -1;
-			break;
-		}
-	}
-
-	free(event);
+	free(args.event);
 	return rc;
 }