Handle NULL addrs / empty OP stacks

dwarf/op/op.go

@@ -3,6 +3,7 @@ package op
 import (
 	"bytes"
 	"encoding/binary"
+	"errors"
 	"fmt"
 
 	"github.com/derekparker/delve/dwarf/util"
@@ -42,6 +43,10 @@ func ExecuteStackProgram(cfa int64, instructions []byte) (int64, error) {
 		}
 	}
 
+	if len(stack) == 0 {
+		return 0, errors.New("empty OP stack")
+	}
+
 	return stack[len(stack)-1], nil
 }
 

proctl/proctl.go

@@ -304,6 +304,9 @@ func (dbp *DebuggedProcess) setChanRecvBreakpoints() (int, error) {
 		if g.ChanRecvBlocked() {
 			ret, err := g.chanRecvReturnAddr(dbp)
 			if err != nil {
+				if _, ok := err.(NullAddrError); ok {
+					continue
+				}
 				return 0, err
 			}
 			if _, err = dbp.TempBreak(ret); err != nil {

proctl/stack.go

@@ -26,6 +26,12 @@ func (thread *ThreadContext) ReturnAddress() (uint64, error) {
 	return locations[0].addr, nil
 }
 
+type NullAddrError struct{}
+
+func (n NullAddrError) Error() string {
+	return "NULL address"
+}
+
 func (dbp *DebuggedProcess) stacktrace(pc, sp uint64, depth int) ([]stackLocation, error) {
 	var (
 		ret       = pc
@@ -41,6 +47,9 @@ func (dbp *DebuggedProcess) stacktrace(pc, sp uint64, depth int) ([]stackLocatio
 		}
 		btoffset += fde.ReturnAddressOffset(ret)
 		retaddr = uintptr(int64(sp) + btoffset + (i * 8))
+		if retaddr == 0 {
+			return nil, NullAddrError{}
+		}
 		_, err = readMemory(dbp.CurrentThread, retaddr, data)
 		if err != nil {
 			return nil, err