From 19ecde04ef1ed2ce5fe5d727162bbe7d596e713f Mon Sep 17 00:00:00 2001
From: Shenghui Wu <793703860@qq.com>
Date: Thu, 2 Feb 2023 18:23:56 +0800
Subject: [PATCH] util: fix memory leak in chunk allocator (#40989)

close pingcap/tidb#40987
---
 util/chunk/alloc.go | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/util/chunk/alloc.go b/util/chunk/alloc.go
index af3385a644389..e9ebaf2e59efd 100644
--- a/util/chunk/alloc.go
+++ b/util/chunk/alloc.go
@@ -129,11 +129,12 @@ func (a *allocator) Reset() {
 
 	//column objects and put them to the column allocator for reuse.
 	for id, pool := range a.columnAlloc.pool {
-		for _, col := range pool.allocColumns {
+		for i, col := range pool.allocColumns {
 			if (len(pool.freeColumns) < a.columnAlloc.freeColumnsPerType) && checkColumnType(id, col) {
 				col.reset()
 				pool.freeColumns = append(pool.freeColumns, col)
 			}
+			pool.allocColumns[i] = nil
 		}
 		pool.allocColumns = pool.allocColumns[:0]
 	}
@@ -196,6 +197,7 @@ func (cList *columnList) pop() *Column {
 		return nil
 	}
 	col := cList.freeColumns[len(cList.freeColumns)-1]
+	cList.freeColumns[len(cList.freeColumns)-1] = nil
 	cList.freeColumns = cList.freeColumns[:len(cList.freeColumns)-1]
 	return col
 }