5 files changed, 102 insertions, 4 deletions
diff --git a/src/runtime/crash_cgo_test.go b/src/runtime/crash_cgo_test.go
index 0680d07a32..140c170ddc 100644
--- a/src/runtime/crash_cgo_test.go
+++ b/src/runtime/crash_cgo_test.go
@@ -254,6 +254,24 @@ func TestCgoCrashTraceback(t *testing.T) {
 	}
 }
 
+func TestCgoCrashTracebackGo(t *testing.T) {
+	t.Parallel()
+	switch platform := runtime.GOOS + "/" + runtime.GOARCH; platform {
+	case "darwin/amd64":
+	case "linux/amd64":
+	case "linux/ppc64le":
+	default:
+		t.Skipf("not yet supported on %s", platform)
+	}
+	got := runTestProg(t, "testprogcgo", "CrashTracebackGo")
+	for i := 1; i <= 3; i++ {
+		want := fmt.Sprintf("main.h%d", i)
+		if !strings.Contains(got, want) {
+			t.Errorf("missing %s", want)
+		}
+	}
+}
+
 func TestCgoTracebackContext(t *testing.T) {
 	t.Parallel()
 	got := runTestProg(t, "testprogcgo", "TracebackContext")
diff --git a/src/runtime/stack_test.go b/src/runtime/stack_test.go
index adfc65384a..43fc5cac55 100644
--- a/src/runtime/stack_test.go
+++ b/src/runtime/stack_test.go
@@ -17,6 +17,7 @@ import (
 	"sync/atomic"
 	"testing"
 	"time"
+	_ "unsafe" // for go:linkname
 )
 
 // TestStackMem measures per-thread stack segment cache behavior.
@@ -851,3 +852,43 @@ func deferHeapAndStack(n int) (r int) {
 
 // Pass a value to escapeMe to force it to escape.
 var escapeMe = func(x interface{}) {}
+
+// Test that when F -> G is inlined and F is excluded from stack
+// traces, G still appears.
+func TestTracebackInlineExcluded(t *testing.T) {
+	defer func() {
+		recover()
+		buf := make([]byte, 4<<10)
+		stk := string(buf[:Stack(buf, false)])
+
+		t.Log(stk)
+
+		if not := "tracebackExcluded"; strings.Contains(stk, not) {
+			t.Errorf("found but did not expect %q", not)
+		}
+		if want := "tracebackNotExcluded"; !strings.Contains(stk, want) {
+			t.Errorf("expected %q in stack", want)
+		}
+	}()
+	tracebackExcluded()
+}
+
+// tracebackExcluded should be excluded from tracebacks. There are
+// various ways this could come up. Linking it to a "runtime." name is
+// rather synthetic, but it's easy and reliable. See issue #42754 for
+// one way this happened in real code.
+//
+//go:linkname tracebackExcluded runtime.tracebackExcluded
+//go:noinline
+func tracebackExcluded() {
+	// Call an inlined function that should not itself be excluded
+	// from tracebacks.
+	tracebackNotExcluded()
+}
+
+// tracebackNotExcluded should be inlined into tracebackExcluded, but
+// should not itself be excluded from the traceback.
+func tracebackNotExcluded() {
+	var x *int
+	*x = 0
+}
diff --git a/src/runtime/testdata/testprogcgo/traceback.go b/src/runtime/testdata/testprogcgo/traceback.go
index 03de894c89..e2d7599131 100644
--- a/src/runtime/testdata/testprogcgo/traceback.go
+++ b/src/runtime/testdata/testprogcgo/traceback.go
@@ -12,6 +12,7 @@ package main
 #cgo CFLAGS: -g -O0
 
 // Defined in traceback_c.c.
+extern int crashInGo;
 int tracebackF1(void);
 void cgoTraceback(void* parg);
 void cgoSymbolizer(void* parg);
@@ -25,9 +26,29 @@ import (
 
 func init() {
 	register("CrashTraceback", CrashTraceback)
+	register("CrashTracebackGo", CrashTracebackGo)
 }
 
 func CrashTraceback() {
 	runtime.SetCgoTraceback(0, unsafe.Pointer(C.cgoTraceback), nil, unsafe.Pointer(C.cgoSymbolizer))
 	C.tracebackF1()
 }
+
+func CrashTracebackGo() {
+	C.crashInGo = 1
+	CrashTraceback()
+}
+
+//export h1
+func h1() {
+	h2()
+}
+
+func h2() {
+	h3()
+}
+
+func h3() {
+	var x *int
+	*x = 0
+}
diff --git a/src/runtime/testdata/testprogcgo/traceback_c.c b/src/runtime/testdata/testprogcgo/traceback_c.c
index 54f44e11fc..56eda8fa8c 100644
--- a/src/runtime/testdata/testprogcgo/traceback_c.c
+++ b/src/runtime/testdata/testprogcgo/traceback_c.c
@@ -2,14 +2,21 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// The C definitions for traceback.go.
+// The C definitions for traceback.go. That file uses //export so
+// it can't put function definitions in the "C" import comment.
 
 #include <stdint.h>
 
 char *p;
 
+int crashInGo;
+extern void h1(void);
+
 int tracebackF3(void) {
-	*p = 0;
+	if (crashInGo)
+		h1();
+	else
+		*p = 0;
 	return 0;
 }
 
diff --git a/src/runtime/traceback.go b/src/runtime/traceback.go
index f3df152535..0825e9e707 100644
--- a/src/runtime/traceback.go
+++ b/src/runtime/traceback.go
@@ -396,13 +396,21 @@ func gentraceback(pc0, sp0, lr0 uintptr, gp *g, skip int, pcbuf *uintptr, max in
 			// If there is inlining info, print the inner frames.
 			if inldata := funcdata(f, _FUNCDATA_InlTree); inldata != nil {
 				inltree := (*[1 << 20]inlinedCall)(inldata)
+				var inlFunc _func
+				inlFuncInfo := funcInfo{&inlFunc, f.datap}
 				for {
 					ix := pcdatavalue(f, _PCDATA_InlTreeIndex, tracepc, nil)
 					if ix < 0 {
 						break
 					}
-					if (flags&_TraceRuntimeFrames) != 0 || showframe(f, gp, nprint == 0, inltree[ix].funcID, lastFuncID) {
-						name := funcnameFromNameoff(f, inltree[ix].func_)
+
+					// Create a fake _func for the
+					// inlined function.
+					inlFunc.nameoff = inltree[ix].func_
+					inlFunc.funcID = inltree[ix].funcID
+
+					if (flags&_TraceRuntimeFrames) != 0 || showframe(inlFuncInfo, gp, nprint == 0, inlFuncInfo.funcID, lastFuncID) {
+						name := funcname(inlFuncInfo)
 						file, line := funcline(f, tracepc)
 						print(name, "(...)\n")
 						print("\t", file, ":", line, "\n")
@@ -811,6 +819,9 @@ func showframe(f funcInfo, gp *g, firstFrame bool, funcID, childID funcID) bool
 // showfuncinfo reports whether a function with the given characteristics should
 // be printed during a traceback.
 func showfuncinfo(f funcInfo, firstFrame bool, funcID, childID funcID) bool {
+	// Note that f may be a synthesized funcInfo for an inlined
+	// function, in which case only nameoff and funcID are set.
+
 	level, _, _ := gotraceback()
 	if level > 1 {
 		// Show all frames.