diff --git a/models/judge_state.js b/models/judge_state.js
index 8c429ff..1943b91 100644
--- a/models/judge_state.js
+++ b/models/judge_state.js
@@ -173,24 +173,28 @@ class JudgeState extends Model {
   }
 
   async updateRelatedInfo(newSubmission) {
-    if (this.type === 0) {
-      if (newSubmission) {
-        await this.loadRelationships();
-        await this.user.refreshSubmitInfo();
-        this.problem.submit_num++;
-        await this.user.save();
-        await this.problem.save();
-      } else if (this.status === 'Accepted') {
-        await this.loadRelationships();
-        await this.user.refreshSubmitInfo();
-        this.problem.ac_num++;
-        await this.user.save();
-        await this.problem.save();
-      }
-    } else if (this.type === 1) {
-      let contest = await Contest.fromID(this.type_info);
-      await contest.newSubmission(this);
-    }
+    await syzoj.utils.lock(['JudgeState::updateRelatedInfo', 'problem', this.problem_id], async () => {
+      await syzoj.utils.lock(['JudgeState::updateRelatedInfo', 'user', this.user_id], async () => {
+        if (this.type === 0) {
+          if (newSubmission) {
+            await this.loadRelationships();
+            await this.user.refreshSubmitInfo();
+            this.problem.submit_num++;
+            await this.user.save();
+            await this.problem.save();
+          } else if (this.status === 'Accepted') {
+            await this.loadRelationships();
+            await this.user.refreshSubmitInfo();
+            this.problem.ac_num++;
+            await this.user.save();
+            await this.problem.save();
+          }
+        } else if (this.type === 1) {
+          let contest = await Contest.fromID(this.type_info);
+          await contest.newSubmission(this);
+        }
+      });
+    });
   }
 
   async rejudge() {