From 71a25b0b762f988c5c7192733fa7702673c9b3a3 Mon Sep 17 00:00:00 2001
From: Dousir9 <736191200@qq.com>
Date: Sat, 14 Jan 2023 14:52:46 +0800
Subject: [PATCH 1/3] add lock at Base

---
 meta/autoid/autoid.go | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/meta/autoid/autoid.go b/meta/autoid/autoid.go
index 8ee99f5939a0e..3a31de31b5475 100644
--- a/meta/autoid/autoid.go
+++ b/meta/autoid/autoid.go
@@ -222,6 +222,8 @@ func SetStep(s int64) {
 
 // Base implements autoid.Allocator Base interface.
 func (alloc *allocator) Base() int64 {
+	alloc.mu.Lock()
+	defer alloc.mu.Unlock()
 	return alloc.base
 }
 

From 3133623c117b05936a627370e3e6c1ff146c6230 Mon Sep 17 00:00:00 2001
From: Dousir9 <736191200@qq.com>
Date: Mon, 16 Jan 2023 22:11:51 +0800
Subject: [PATCH 2/3] add lock on allocator.End

---
 meta/autoid/autoid.go | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/meta/autoid/autoid.go b/meta/autoid/autoid.go
index 3a31de31b5475..bfbb04b72a906 100644
--- a/meta/autoid/autoid.go
+++ b/meta/autoid/autoid.go
@@ -229,6 +229,8 @@ func (alloc *allocator) Base() int64 {
 
 // End implements autoid.Allocator End interface.
 func (alloc *allocator) End() int64 {
+	alloc.mu.Lock()
+	defer alloc.mu.Unlock()
 	return alloc.end
 }
 

From 9c2f2be355a6eb4a0bd63421c3d6551740fb59fb Mon Sep 17 00:00:00 2001
From: Dousir9 <736191200@qq.com>
Date: Mon, 16 Jan 2023 22:12:56 +0800
Subject: [PATCH 3/3] add unit test

---
 meta/autoid/autoid_test.go | 55 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 55 insertions(+)

diff --git a/meta/autoid/autoid_test.go b/meta/autoid/autoid_test.go
index 16cfc7c64ac1c..b414378beea66 100644
--- a/meta/autoid/autoid_test.go
+++ b/meta/autoid/autoid_test.go
@@ -20,6 +20,7 @@ import (
 	"math"
 	"math/rand"
 	"sync"
+	"sync/atomic"
 	"testing"
 	"time"
 
@@ -593,3 +594,57 @@ func TestAllocComputationIssue(t *testing.T) {
 	require.Equal(t, int64(7), min)
 	require.Equal(t, int64(13), max)
 }
+
+func TestIssue40584(t *testing.T) {
+	store, err := mockstore.NewMockStore()
+	require.NoError(t, err)
+	defer func() {
+		err := store.Close()
+		require.NoError(t, err)
+	}()
+
+	ctx := kv.WithInternalSourceType(context.Background(), kv.InternalTxnMeta)
+	err = kv.RunInNewTxn(ctx, store, false, func(ctx context.Context, txn kv.Transaction) error {
+		m := meta.NewMeta(txn)
+		err = m.CreateDatabase(&model.DBInfo{ID: 1, Name: model.NewCIStr("a")})
+		require.NoError(t, err)
+		err = m.CreateTableOrView(1, &model.TableInfo{ID: 1, Name: model.NewCIStr("t")})
+		require.NoError(t, err)
+		return nil
+	})
+	require.NoError(t, err)
+
+	alloc := autoid.NewAllocator(store, 1, 1, false, autoid.RowIDAllocType)
+	require.NotNil(t, alloc)
+
+	finishAlloc := make(chan bool)
+	finishBase := make(chan bool)
+	var done int32 = 0
+
+	// call allocator.Alloc and allocator.Base in parallel for 3 seconds to detect data race
+	go func() {
+		for {
+			alloc.Alloc(ctx, 1, 1, 1)
+			if atomic.LoadInt32(&done) > 0 {
+				break
+			}
+		}
+		finishAlloc <- true
+	}()
+
+	go func() {
+		for {
+			alloc.Base()
+			if atomic.LoadInt32(&done) > 0 {
+				break
+			}
+		}
+		finishBase <- true
+	}()
+
+	runTime := time.NewTimer(time.Second * 3)
+	<-runTime.C
+	atomic.AddInt32(&done, 1)
+	<-finishAlloc
+	<-finishBase
+}