diff --git a/src/io/pibinarylog.cpp b/src/io/pibinarylog.cpp
index c8bcbca2..88dd04a9 100644
--- a/src/io/pibinarylog.cpp
+++ b/src/io/pibinarylog.cpp
@@ -359,6 +359,7 @@ bool PIBinaryLog::checkFileHeader() {
 
 
 PIBinaryLog::BinLogRecord PIBinaryLog::readRecord() {
+	logmutex.lock();
 	PIByteArray ba;
 	BinLogRecord br;
 	lastrecord.id = 0;
@@ -369,6 +370,7 @@ PIBinaryLog::BinLogRecord PIBinaryLog::readRecord() {
 		ba >> br.id >> br.size >> br.timestamp;
 	} else {
 		br.id = -1;
+		logmutex.unlock();
 		return br;
 	}
 	if (br.id > 0 && br.size > 0) {
@@ -379,6 +381,7 @@ PIBinaryLog::BinLogRecord PIBinaryLog::readRecord() {
 	lastrecord = br;
 	if (br.id == 0) fileError();
 	moveIndex(index_pos.value(file.pos(), -1));
+	logmutex.unlock();
 	return br;
 }
 
@@ -497,12 +500,14 @@ bool PIBinaryLog::createIndex() {
 
 
 void PIBinaryLog::seekTo(int rindex) {
+	logmutex.lock();
 	if (rindex < index.size_s() && rindex >= 0) {
 		file.seek(index[rindex].pos);
 		moveIndex(index_pos.value(file.pos(), -1));
 		play_time = index[rindex].timestamp.toMilliseconds();
 		lastrecord.timestamp = index[rindex].timestamp;
 	}
+	logmutex.unlock();
 }
 
 
diff --git a/src/io/pibinarylog.h b/src/io/pibinarylog.h
index 47a1611b..554192dc 100644
--- a/src/io/pibinarylog.h
+++ b/src/io/pibinarylog.h
@@ -293,6 +293,7 @@ private:
 	PIFile file;
 	BinLogRecord lastrecord;
 	PISystemTime startlogtime, play_delay, split_time;
+	PIMutex logmutex;
 	double play_time, play_speed;
 	llong split_size;
 	int write_count, split_count, default_id, current_index;