proc: fix bad cached goroutines after a call injection (#1926)

Inserts a call to ClearAllGCache into stepInstructionOut so that cached
goroutine state is not inconsistent after an injected function call.\

Fixes #1925

pkg/proc/proc.go

@@ -330,6 +330,7 @@ func disassembleCurrentInstruction(p Process, thread Thread) ([]AsmInstruction,
 // This function is used to step out of runtime.Breakpoint as well as
 // runtime.debugCallV1.
 func stepInstructionOut(dbp *Target, curthread Thread, fnname1, fnname2 string) error {
+	defer dbp.ClearAllGCache()
 	for {
 		if err := curthread.StepInstruction(); err != nil {
 			return err

pkg/proc/proc_test.go

@@ -4174,9 +4174,6 @@ func TestReadDeferArgs(t *testing.T) {
 }
 
 func TestIssue1374(t *testing.T) {
-	if runtime.GOARCH == "arm64" || runtime.GOARCH == "386" {
-		t.Skip(fmt.Errorf("%s does not support FunctionCall for now", runtime.GOARCH))
-	}
 	// Continue did not work when stopped at a breakpoint immediately after calling CallFunction.
 	protest.MustSupportFunctionCalls(t, testBackend)
 	withTestProcess("issue1374", t, func(p *proc.Target, fixture protest.Fixture) {
@@ -4396,9 +4393,6 @@ func TestCallConcurrent(t *testing.T) {
 	if runtime.GOOS == "freebsd" {
 		t.Skip("test is not valid on FreeBSD")
 	}
-	if runtime.GOARCH == "arm64" || runtime.GOARCH == "386" {
-		t.Skip(fmt.Sprintf("%s does not support FunctionCall for now", runtime.GOARCH))
-	}
 
 	protest.MustSupportFunctionCalls(t, testBackend)
 	withTestProcess("teststepconcurrent", t, func(p *proc.Target, fixture protest.Fixture) {
@@ -4748,3 +4742,20 @@ func TestBackwardNextDeferPanic(t *testing.T) {
 		{contReverseNext, 28},
 	})
 }
+
+func TestIssue1925(t *testing.T) {
+	// Calling a function should not leave cached goroutine information in an
+	// inconsistent state.
+	// In particular the stepInstructionOut function called at the end of a
+	// 'call' procedure should clean the G cache like every other function
+	// altering the state of the target process.
+	protest.MustSupportFunctionCalls(t, testBackend)
+	withTestProcess("testvariables2", t, func(p *proc.Target, fixture protest.Fixture) {
+		assertNoError(proc.Continue(p), t, "Continue()")
+		assertNoError(proc.EvalExpressionWithCalls(p, p.SelectedGoroutine(), "afunc(2)", normalLoadConfig, true), t, "Call")
+		t.Logf("%v\n", p.SelectedGoroutine().CurrentLoc)
+		if loc := p.SelectedGoroutine().CurrentLoc; loc.File != fixture.Source {
+			t.Errorf("wrong location for selected goroutine after call: %s:%d", loc.File, loc.Line)
+		}
+	})
+}

pkg/proc/test/support.go

@@ -315,6 +315,9 @@ func MustSupportFunctionCalls(t *testing.T, testBackend string) {
 	if runtime.GOOS == "darwin" && os.Getenv("TRAVIS") == "true" {
 		t.Skip("function call injection tests are failing on macOS on Travis-CI (see #1802)")
 	}
+	if runtime.GOARCH == "arm64" || runtime.GOARCH == "386" {
+		t.Skip(fmt.Errorf("%s does not support FunctionCall for now", runtime.GOARCH))
+	}
 }
 
 // DefaultTestBackend changes the value of testBackend to be the default