proc: bugfix: crash when a negative depth is used for Stacktrace

proc/stack.go

@@ -2,6 +2,7 @@ package proc
 
 import (
 	"encoding/binary"
+	"errors"
 	"fmt"
 )
 
@@ -164,6 +165,9 @@ func (dbp *Process) frameInfo(pc, sp uint64, top bool) (Stackframe, error) {
 }
 
 func (dbp *Process) stacktrace(pc, sp uint64, depth int) ([]Stackframe, error) {
+	if depth < 0 {
+		return nil, errors.New("negative maximum stack depth")
+	}
 	frames := make([]Stackframe, 0, depth+1)
 	it := newStackIterator(dbp, pc, sp)
 	for it.Next() {

service/test/integration_test.go

@@ -798,3 +798,16 @@ func TestIssue355(t *testing.T) {
 		assertError(err, t, "FindLocation()")
 	})
 }
+
+func TestNegativeStackDepthBug(t *testing.T) {
+	// After the target process has terminated should return an error but not crash
+	withTestClient("continuetestprog", t, func(c service.Client) {
+		_, err := c.CreateBreakpoint(&api.Breakpoint{FunctionName: "main.sayhi", Line: -1})
+		assertNoError(err, t, "CreateBreakpoint()")
+		ch := c.Continue()
+		state := <-ch
+		assertNoError(state.Err, t, "Continue()")
+		_, err = c.Stacktrace(-1, -2, true)
+		assertError(err, t, "Stacktrace()")
+	})
+}