From 166cfd2c878a806897526ba7bfecda060323cba5 Mon Sep 17 00:00:00 2001 From: Russ Cox Date: Wed, 13 Jan 2016 12:45:52 -0500 Subject: [PATCH] runtime: arrange to show a few local variables when cgoCheckUnknownPointer panics For #13934. Change-Id: Id399e35598def96f8bb89b9fcd1bf14ee06e2e62 Reviewed-on: https://go-review.googlesource.com/18612 Reviewed-by: Ian Lance Taylor Run-TryBot: Russ Cox TryBot-Result: Gobot Gobot --- src/runtime/cgocall.go | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/src/runtime/cgocall.go b/src/runtime/cgocall.go index 9710c418b2..3b395fb8cd 100644 --- a/src/runtime/cgocall.go +++ b/src/runtime/cgocall.go @@ -498,7 +498,8 @@ func cgoCheckArg(t *_type, p unsafe.Pointer, indir, top bool, msg string) { // cgoCheckUnknownPointer is called for an arbitrary pointer into Go // memory. It checks whether that Go memory contains any other // pointer into Go memory. If it does, we panic. -func cgoCheckUnknownPointer(p unsafe.Pointer, msg string) { +// The return values are unused but useful to see in panic tracebacks. +func cgoCheckUnknownPointer(p unsafe.Pointer, msg string) (base, i uintptr) { if cgoInRange(p, mheap_.arena_start, mheap_.arena_used) { if !inheap(uintptr(p)) { // This pointer is either to a stack or to an @@ -508,12 +509,13 @@ func cgoCheckUnknownPointer(p unsafe.Pointer, msg string) { panic(errorString("cgo argument has invalid Go pointer")) } - base, hbits, span := heapBitsForObject(uintptr(p), 0, 0) + b, hbits, span := heapBitsForObject(uintptr(p), 0, 0) + base = b if base == 0 { return } n := span.elemsize - for i := uintptr(0); i < n; i += sys.PtrSize { + for i = uintptr(0); i < n; i += sys.PtrSize { bits := hbits.bits() if i >= 2*sys.PtrSize && bits&bitMarked == 0 { // No more possible pointers. @@ -539,6 +541,8 @@ func cgoCheckUnknownPointer(p unsafe.Pointer, msg string) { // In the text or noptr sections, we know that the // pointer does not point to a Go pointer. } + + return } // cgoIsGoPointer returns whether the pointer is a Go pointer--a -- 2.50.0