runtime: clarify error when returning unpinned pointers

[gostls13.git] / src / runtime / cgocall.go

diff --git a/src/runtime/cgocall.go b/src/runtime/cgocall.go
index 73efd28491fe67231c15c1006961a09a1cb5fc03..6c2fd8f907a5f6cd48b45bf9b2a860a9fb0dbbf7 100644 (file)
--- a/src/runtime/cgocall.go
+++ b/src/runtime/cgocall.go
@@ -533,13 +533,13 @@ func cgoCheckPointer(ptr any, arg any) {
 }
 
 const cgoCheckPointerFail = "cgo argument has Go pointer to unpinned Go pointer"
-const cgoResultFail = "cgo result has Go pointer"
+const cgoResultFail = "cgo result is unpinned Go pointer or points to unpinned Go pointer"
 
 // cgoCheckArg is the real work of cgoCheckPointer. The argument p
 // is either a pointer to the value (of type t), or the value itself,
 // depending on indir. The top parameter is whether we are at the top
 // level, where Go pointers are allowed. Go pointers to pinned objects are
-// always allowed.
+// allowed as long as they don't reference other unpinned pointers.
 func cgoCheckArg(t *_type, p unsafe.Pointer, indir, top bool, msg string) {
        if t.PtrBytes == 0 || p == nil {
                // If the type has no pointers there is nothing to do.
@@ -726,8 +726,8 @@ func cgoInRange(p unsafe.Pointer, start, end uintptr) bool {
 }
 
 // cgoCheckResult is called to check the result parameter of an
-// exported Go function. It panics if the result is or contains a Go
-// pointer.
+// exported Go function. It panics if the result is or contains any
+// other pointer into unpinned Go memory.
 func cgoCheckResult(val any) {
        if !goexperiment.CgoCheck2 && debug.cgocheck == 0 {
                return