diff --git a/go.mod b/go.mod
index f2c52e5..ef8fa7c 100644
--- a/go.mod
+++ b/go.mod
@@ -4,8 +4,9 @@ go 1.21
 
 require (
 	github.com/ncruces/julianday v1.0.0
+	github.com/ncruces/sort v0.1.2
 	github.com/psanford/httpreadat v0.1.0
-	github.com/tetratelabs/wazero v1.7.2
+	github.com/tetratelabs/wazero v1.7.3
 	golang.org/x/crypto v0.24.0
 	golang.org/x/sync v0.7.0
 	golang.org/x/sys v0.21.0
@@ -13,6 +14,4 @@ require (
 	lukechampine.com/adiantum v1.1.1
 )
 
-require github.com/ncruces/sort v0.1.2
-
 retract v0.4.0 // tagged from the wrong branch
diff --git a/go.sum b/go.sum
index f40e765..bbc1b30 100644
--- a/go.sum
+++ b/go.sum
@@ -4,8 +4,8 @@ github.com/ncruces/sort v0.1.2 h1:zKQ9CA4fpHPF6xsUhRTfi5EEryspuBpe/QA4VWQOV1U=
 github.com/ncruces/sort v0.1.2/go.mod h1:vEJUTBJtebIuCMmXD18GKo5GJGhsay+xZFOoBEIXFmE=
 github.com/psanford/httpreadat v0.1.0 h1:VleW1HS2zO7/4c7c7zNl33fO6oYACSagjJIyMIwZLUE=
 github.com/psanford/httpreadat v0.1.0/go.mod h1:Zg7P+TlBm3bYbyHTKv/EdtSJZn3qwbPwpfZ/I9GKCRE=
-github.com/tetratelabs/wazero v1.7.2 h1:1+z5nXJNwMLPAWaTePFi49SSTL0IMx/i3Fg8Yc25GDc=
-github.com/tetratelabs/wazero v1.7.2/go.mod h1:ytl6Zuh20R/eROuyDaGPkp82O9C/DJfXAwJfQ3X6/7Y=
+github.com/tetratelabs/wazero v1.7.3 h1:PBH5KVahrt3S2AHgEjKu4u+LlDbbk+nsGE3KLucy6Rw=
+github.com/tetratelabs/wazero v1.7.3/go.mod h1:ytl6Zuh20R/eROuyDaGPkp82O9C/DJfXAwJfQ3X6/7Y=
 golang.org/x/crypto v0.24.0 h1:mnl8DM0o513X8fdIkmyFE/5hTYxbwYOjDS/+rK6qpRI=
 golang.org/x/crypto v0.24.0/go.mod h1:Z1PMYSOR5nyMcyAVAIQSKCDwalqy85Aqn1x3Ws4L5DM=
 golang.org/x/sync v0.7.0 h1:YsImfSBoP9QPYL0xyKJPq0gcaJdG3rInoqxTWbfQu9M=
diff --git a/gormlite/go.mod b/gormlite/go.mod
index 7808d5c..da246c7 100644
--- a/gormlite/go.mod
+++ b/gormlite/go.mod
@@ -11,6 +11,6 @@ require (
 	github.com/jinzhu/inflection v1.0.0 // indirect
 	github.com/jinzhu/now v1.1.5 // indirect
 	github.com/ncruces/julianday v1.0.0 // indirect
-	github.com/tetratelabs/wazero v1.7.2 // indirect
+	github.com/tetratelabs/wazero v1.7.3 // indirect
 	golang.org/x/sys v0.21.0 // indirect
 )
diff --git a/gormlite/go.sum b/gormlite/go.sum
index bc71310..81c189e 100644
--- a/gormlite/go.sum
+++ b/gormlite/go.sum
@@ -6,8 +6,8 @@ github.com/ncruces/go-sqlite3 v0.16.1 h1:1wHv7s8y+fWK44UIliotJ42ZV41A5T0sjIAqGmn
 github.com/ncruces/go-sqlite3 v0.16.1/go.mod h1:feFXbBcbLtxNk6XWG1ROt8MS9+E45yCW3G8o4ixIqZ8=
 github.com/ncruces/julianday v1.0.0 h1:fH0OKwa7NWvniGQtxdJRxAgkBMolni2BjDHaWTxqt7M=
 github.com/ncruces/julianday v1.0.0/go.mod h1:Dusn2KvZrrovOMJuOt0TNXL6tB7U2E8kvza5fFc9G7g=
-github.com/tetratelabs/wazero v1.7.2 h1:1+z5nXJNwMLPAWaTePFi49SSTL0IMx/i3Fg8Yc25GDc=
-github.com/tetratelabs/wazero v1.7.2/go.mod h1:ytl6Zuh20R/eROuyDaGPkp82O9C/DJfXAwJfQ3X6/7Y=
+github.com/tetratelabs/wazero v1.7.3 h1:PBH5KVahrt3S2AHgEjKu4u+LlDbbk+nsGE3KLucy6Rw=
+github.com/tetratelabs/wazero v1.7.3/go.mod h1:ytl6Zuh20R/eROuyDaGPkp82O9C/DJfXAwJfQ3X6/7Y=
 golang.org/x/sys v0.21.0 h1:rF+pYz3DAGSQAxAu1CbC7catZg4ebC4UIeIhKxBZvws=
 golang.org/x/sys v0.21.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
 golang.org/x/text v0.16.0 h1:a94ExnEXNtEwYLGJSIUxnWoxoRz/ZcCsV63ROupILh4=
diff --git a/internal/util/json.go b/internal/util/json.go
index c0ba38c..7f6849a 100644
--- a/internal/util/json.go
+++ b/internal/util/json.go
@@ -26,7 +26,7 @@ func (j JSON) Scan(value any) error {
 		buf = v.AppendFormat(buf, time.RFC3339Nano)
 		buf = append(buf, '"')
 	case nil:
-		buf = append(buf, "null"...)
+		buf = []byte("null")
 	default:
 		panic(AssertErr())
 	}
diff --git a/stmt.go b/stmt.go
index ac40e38..381a7d0 100644
--- a/stmt.go
+++ b/stmt.go
@@ -564,7 +564,7 @@ func (s *Stmt) ColumnJSON(col int, ptr any) error {
 	var data []byte
 	switch s.ColumnType(col) {
 	case NULL:
-		data = append(data, "null"...)
+		data = []byte("null")
 	case TEXT:
 		data = s.ColumnRawText(col)
 	case BLOB:
diff --git a/value.go b/value.go
index d0edf21..1894ff4 100644
--- a/value.go
+++ b/value.go
@@ -177,7 +177,7 @@ func (v Value) JSON(ptr any) error {
 	var data []byte
 	switch v.Type() {
 	case NULL:
-		data = append(data, "null"...)
+		data = []byte("null")
 	case TEXT:
 		data = v.RawText()
 	case BLOB:
diff --git a/vfs/memdb/memdb.go b/vfs/memdb/memdb.go
index 8dc57ab..f21335d 100644
--- a/vfs/memdb/memdb.go
+++ b/vfs/memdb/memdb.go
@@ -75,11 +75,6 @@ func (memVFS) FullPathname(name string) (string, error) {
 type memDB struct {
 	name string
 
-	// +checklocks:lockMtx
-	pending *memFile
-	// +checklocks:lockMtx
-	reserved *memFile
-
 	// +checklocks:dataMtx
 	data []*[sectorSize]byte
 
@@ -88,6 +83,10 @@ type memDB struct {
 
 	// +checklocks:lockMtx
 	shared int
+	// +checklocks:lockMtx
+	reserved bool
+	// +checklocks:lockMtx
+	pending bool
 
 	// +checklocks:memoryMtx
 	refs int
@@ -214,24 +213,24 @@ func (m *memFile) Lock(lock vfs.LockLevel) error {
 
 	switch lock {
 	case vfs.LOCK_SHARED:
-		if m.pending != nil {
+		if m.pending {
 			return sqlite3.BUSY
 		}
 		m.shared++
 
 	case vfs.LOCK_RESERVED:
-		if m.reserved != nil {
+		if m.reserved {
 			return sqlite3.BUSY
 		}
-		m.reserved = m
+		m.reserved = true
 
 	case vfs.LOCK_EXCLUSIVE:
 		if m.lock < vfs.LOCK_PENDING {
-			if m.pending != nil {
+			if m.pending {
 				return sqlite3.BUSY
 			}
 			m.lock = vfs.LOCK_PENDING
-			m.pending = m
+			m.pending = true
 		}
 
 		for before := time.Now(); m.shared > 1; {
@@ -256,11 +255,11 @@ func (m *memFile) Unlock(lock vfs.LockLevel) error {
 	m.lockMtx.Lock()
 	defer m.lockMtx.Unlock()
 
-	if m.pending == m {
-		m.pending = nil
+	if m.pending && m.lock >= vfs.LOCK_PENDING {
+		m.pending = false
 	}
-	if m.reserved == m {
-		m.reserved = nil
+	if m.reserved && m.lock >= vfs.LOCK_RESERVED {
+		m.reserved = false
 	}
 	if lock < vfs.LOCK_SHARED {
 		m.shared--
@@ -275,7 +274,7 @@ func (m *memFile) CheckReservedLock() (bool, error) {
 	}
 	m.lockMtx.Lock()
 	defer m.lockMtx.Unlock()
-	return m.reserved != nil, nil
+	return m.reserved, nil
 }
 
 func (m *memFile) SectorSize() int {
diff --git a/vfs/shm_bsd.go b/vfs/shm_bsd.go
index 2f61cd3..8c2abee 100644
--- a/vfs/shm_bsd.go
+++ b/vfs/shm_bsd.go
@@ -101,13 +101,13 @@ func (s *vfsShm) shmOpen() (rc _ErrorCode) {
 		return _OK
 	}
 
-	// Open file read-write, as it will be shared.
+	// Always open file read-write, as it will be shared.
 	f, err := os.OpenFile(s.path,
 		unix.O_RDWR|unix.O_CREAT|unix.O_NOFOLLOW, 0666)
 	if err != nil {
 		return _CANTOPEN
 	}
-	// Close if file if it's not nil.
+	// Closes file if it's not nil.
 	defer func() { f.Close() }()
 
 	fi, err := f.Stat()
@@ -145,17 +145,14 @@ func (s *vfsShm) shmOpen() (rc _ErrorCode) {
 		info: fi,
 		refs: 1,
 	}
-	f = nil
-	add := true
+	f = nil // Don't close the file.
 	for i, g := range vfsShmFiles {
 		if g == nil {
 			vfsShmFiles[i] = s.vfsShmFile
-			add = false
+			return rc
 		}
 	}
-	if add {
-		vfsShmFiles = append(vfsShmFiles, s.vfsShmFile)
-	}
+	vfsShmFiles = append(vfsShmFiles, s.vfsShmFile)
 	return rc
 }