diff --git a/.golangci.yml b/.golangci.yml
index 483c67ad5e..ad75ddf96d 100644
--- a/.golangci.yml
+++ b/.golangci.yml
@@ -11,7 +11,6 @@ linters:
     - cyclop
     - depguard
     - dupl
-    - dupword
     - errname
     - errorlint
     - exhaustive
@@ -43,7 +42,6 @@ linters:
     - testpackage
     - thelper
     - tparallel
-    - unconvert
     - unparam
     - usestdlibvars
     - varnamelen
diff --git a/brotli.go b/brotli.go
index c829c39fa7..032bd953ec 100644
--- a/brotli.go
+++ b/brotli.go
@@ -132,7 +132,17 @@ func WriteBrotliLevel(w io.Writer, p []byte, level int) (int, error) {
 	}
 }
 
-var stacklessWriteBrotli = stackless.NewFunc(nonblockingWriteBrotli)
+var (
+	stacklessWriteBrotliOnce sync.Once
+	stacklessWriteBrotliFunc func(ctx interface{}) bool
+)
+
+func stacklessWriteBrotli(ctx interface{}) {
+	stacklessWriteBrotliOnce.Do(func() {
+		stacklessWriteBrotliFunc = stackless.NewFunc(nonblockingWriteBrotli)
+	})
+	stacklessWriteBrotliFunc(ctx)
+}
 
 func nonblockingWriteBrotli(ctxv interface{}) {
 	ctx := ctxv.(*compressCtx)
diff --git a/bytesconv_test.go b/bytesconv_test.go
index c9034ec0e5..444981061a 100644
--- a/bytesconv_test.go
+++ b/bytesconv_test.go
@@ -37,7 +37,7 @@ func TestAppendHTMLEscape(t *testing.T) {
 		allcases[i] = byte(i)
 	}
 	res := string(AppendHTMLEscape(nil, string(allcases)))
-	expect := string(html.EscapeString(string(allcases)))
+	expect := html.EscapeString(string(allcases))
 	if res != expect {
 		t.Fatalf("unexpected string %q. Expecting %q.", res, expect)
 	}
diff --git a/client.go b/client.go
index 02456d313f..498de057c7 100644
--- a/client.go
+++ b/client.go
@@ -1474,6 +1474,7 @@ func (c *HostClient) acquireConn(reqTimeout time.Duration, connectionClose bool)
 			return nil, ErrNoFreeConns
 		}
 
+		//nolint:dupword
 		// reqTimeout    c.MaxConnWaitTimeout   wait duration
 		//     d1                 d2            min(d1, d2)
 		//  0(not set)            d2            d2
@@ -2542,8 +2543,8 @@ func (c *PipelineClient) newConnClient() *pipelineConnClient {
 }
 
 // ErrPipelineOverflow may be returned from PipelineClient.Do*
-// if the requests' queue is overflown.
-var ErrPipelineOverflow = errors.New("pipelined requests' queue has been overflown. Increase MaxConns and/or MaxPendingRequests")
+// if the requests' queue is overflowed.
+var ErrPipelineOverflow = errors.New("pipelined requests' queue has been overflowed. Increase MaxConns and/or MaxPendingRequests")
 
 // DefaultMaxPendingRequests is the default value
 // for PipelineClient.MaxPendingRequests.
diff --git a/compress.go b/compress.go
index 8494d569be..1f44f1e6fc 100644
--- a/compress.go
+++ b/compress.go
@@ -177,7 +177,17 @@ func WriteGzipLevel(w io.Writer, p []byte, level int) (int, error) {
 	}
 }
 
-var stacklessWriteGzip = stackless.NewFunc(nonblockingWriteGzip)
+var (
+	stacklessWriteGzipOnce sync.Once
+	stacklessWriteGzipFunc func(ctx interface{}) bool
+)
+
+func stacklessWriteGzip(ctx interface{}) {
+	stacklessWriteGzipOnce.Do(func() {
+		stacklessWriteGzipFunc = stackless.NewFunc(nonblockingWriteGzip)
+	})
+	stacklessWriteGzipFunc(ctx)
+}
 
 func nonblockingWriteGzip(ctxv interface{}) {
 	ctx := ctxv.(*compressCtx)
@@ -270,7 +280,17 @@ func WriteDeflateLevel(w io.Writer, p []byte, level int) (int, error) {
 	}
 }
 
-var stacklessWriteDeflate = stackless.NewFunc(nonblockingWriteDeflate)
+var (
+	stacklessWriteDeflateOnce sync.Once
+	stacklessWriteDeflateFunc func(ctx interface{}) bool
+)
+
+func stacklessWriteDeflate(ctx interface{}) {
+	stacklessWriteDeflateOnce.Do(func() {
+		stacklessWriteDeflateFunc = stackless.NewFunc(nonblockingWriteDeflate)
+	})
+	stacklessWriteDeflateFunc(ctx)
+}
 
 func nonblockingWriteDeflate(ctxv interface{}) {
 	ctx := ctxv.(*compressCtx)
diff --git a/fs.go b/fs.go
index 9ada758843..c231d8031c 100644
--- a/fs.go
+++ b/fs.go
@@ -870,7 +870,7 @@ func (cm *inMemoryCacheManager) GetFileFromCache(cacheKind CacheKind, path strin
 	fileCache := cm.getFsCache(cacheKind)
 
 	cm.cacheLock.Lock()
-	ff, ok := fileCache[string(path)]
+	ff, ok := fileCache[path]
 	if ok {
 		ff.readersCount++
 	}
@@ -1594,7 +1594,7 @@ func (h *fsHandler) newFSFile(f fs.File, fileInfo fs.FileInfo, compressed bool,
 }
 
 func readFileHeader(f io.Reader, compressed bool, fileEncoding string) ([]byte, error) {
-	r := io.Reader(f)
+	r := f
 	var (
 		br *brotli.Reader
 		zr *gzip.Reader
diff --git a/http_test.go b/http_test.go
index 0091566c7a..7b526cbd85 100644
--- a/http_test.go
+++ b/http_test.go
@@ -3022,7 +3022,7 @@ func TestResponseBodyStream(t *testing.T) {
 			}
 		})
 
-		t.Run("limit response body size size", func(t *testing.T) {
+		t.Run("limit response body size", func(t *testing.T) {
 			t.Parallel()
 
 			client := Client{StreamResponseBody: true, MaxResponseBodySize: 20}
diff --git a/stackless/writer.go b/stackless/writer.go
index b0d3e8dd96..347e464a29 100644
--- a/stackless/writer.go
+++ b/stackless/writer.go
@@ -4,6 +4,7 @@ import (
 	"errors"
 	"fmt"
 	"io"
+	"sync"
 
 	"github.com/valyala/bytebufferpool"
 )
@@ -98,7 +99,17 @@ func (w *writer) do(op op) error {
 
 var errHighLoad = errors.New("cannot compress data due to high load")
 
-var stacklessWriterFunc = NewFunc(writerFunc)
+var (
+	stacklessWriterFuncOnce sync.Once
+	stacklessWriterFuncFunc func(ctx interface{}) bool
+)
+
+func stacklessWriterFunc(ctx interface{}) bool {
+	stacklessWriterFuncOnce.Do(func() {
+		stacklessWriterFuncFunc = NewFunc(writerFunc)
+	})
+	return stacklessWriterFuncFunc(ctx)
+}
 
 func writerFunc(ctx interface{}) {
 	w := ctx.(*writer)