map: avoid misleading error message for storage maps

map.go

@@ -673,7 +673,7 @@ func handleMapCreateError(attr sys.MapCreateAttr, spec *MapSpec, err error) erro
 		return fmt.Errorf("map create: %w (MEMLOCK may be too low, consider rlimit.RemoveMemlock)", err)
 	}
 	if errors.Is(err, unix.EINVAL) {
-		if spec.MaxEntries == 0 {
+		if spec.MaxEntries == 0 && !spec.Type.requiresZeroMaxEntries() {
 			return fmt.Errorf("map create: %w (MaxEntries may be incorrectly set to zero)", err)
 		}
 		if spec.Type == UnspecifiedMap {

map_test.go

@@ -2323,3 +2323,67 @@ func ExampleMap_Iterate_nestedMapsAndProgramArrays() {
 		panic(fmt.Sprint("Iterator encountered an error:", err))
 	}
 }
+
+func TestMapCreateStorageMisleadingError(t *testing.T) {
+	tests := []struct {
+		name    string
+		mapType MapType
+		version string
+	}{
+		{"SkStorage", SkStorage, "5.2"},
+		{"InodeStorage", InodeStorage, "5.10"},
+		{"TaskStorage", TaskStorage, "5.11"},
+		{"CgroupStorage", CgroupStorage, "6.2"},
+		{"CGroupStorage", CGroupStorage, "4.19"},
+		{"PerCPUCGroupStorage", PerCPUCGroupStorage, "4.20"},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			testutils.SkipOnOldKernel(t, tt.version, tt.name+" map")
+
+			spec := &MapSpec{
+				Type:       tt.mapType,
+				KeySize:    4,
+				ValueSize:  4,
+				MaxEntries: 0,
+				Flags:      sys.BPF_F_NO_PREALLOC,
+			}
+
+			_, err := NewMap(spec)
+			qt.Assert(t, qt.IsNotNil(err), qt.Commentf("Expected map creation to fail"))
+
+			if errors.Is(err, unix.EINVAL) {
+				qt.Assert(t, qt.Not(qt.StringContains(err.Error(), "MaxEntries may be incorrectly set to zero")))
+			}
+		})
+	}
+}
+
+func TestMapCreateZeroMaxEntriesError(t *testing.T) {
+	tests := []struct {
+		name    string
+		mapType MapType
+	}{
+		{"Hash", Hash},
+		{"Array", Array},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			spec := &MapSpec{
+				Type:       tt.mapType,
+				KeySize:    4,
+				ValueSize:  4,
+				MaxEntries: 0, // Invalid zero value
+			}
+
+			_, err := NewMap(spec)
+			qt.Assert(t, qt.IsNotNil(err), qt.Commentf("Expected map creation to fail"))
+
+			if errors.Is(err, unix.EINVAL) {
+				qt.Assert(t, qt.StringContains(err.Error(), "MaxEntries may be incorrectly set to zero"))
+			}
+		})
+	}
+}

types.go

@@ -188,6 +188,16 @@ func (mt MapType) mustHaveNoPrealloc() bool {
 	return false
 }
 
+// requiresZeroMaxEntries returns true if the map type requires MaxEntries to be zero.
+func (mt MapType) requiresZeroMaxEntries() bool {
+	switch mt {
+	case CgroupStorage, CGroupStorage, PerCPUCGroupStorage, InodeStorage, TaskStorage, SkStorage:
+		return true
+	}
+
+	return false
+}
+
 // ProgramType of the eBPF program
 type ProgramType uint32