--- x/fs/proc/task_mmu.c
+++ y/fs/proc/task_mmu.c
@@ -586,6 +586,7 @@ no_vma:
 	return ERR_PTR(-ENOENT);
 }
 
+static DEFINE_MUTEX(query_mutex);
 static int do_procmap_query(struct proc_maps_private *priv, void __user *uarg)
 {
 	struct procmap_query karg;
@@ -630,6 +631,7 @@ static int do_procmap_query(struct proc_
 		return -ENOMEM;
 	}
 
+	mutex_lock(&query_mutex);
 	err = query_vma_setup(priv);
 	if (err)
 		goto fail_vma_setup;
@@ -712,6 +714,7 @@ static int do_procmap_query(struct proc_
 
 	/* unlock vma or mmap_lock, and put mm_struct before copying data to user */
 	query_vma_teardown(priv);
+	mutex_unlock(&query_mutex);
 	mmput(mm);
 
 	if (karg.vma_name_size && copy_to_user(u64_to_user_ptr(karg.vma_name_addr),
@@ -733,6 +736,7 @@ static int do_procmap_query(struct proc_
 out:
 	query_vma_teardown(priv);
 fail_vma_setup:
+	mutex_unlock(&query_mutex);
 	mmput(mm);
 	kfree(name_buf);
 	return err;