9 files changed, 61 insertions, 14 deletions
diff --git a/src/runtime/crash_test.go b/src/runtime/crash_test.go
index 43cea9008a..715b2da232 100644
--- a/src/runtime/crash_test.go
+++ b/src/runtime/crash_test.go
@@ -10,6 +10,7 @@ import (
 	"os"
 	"os/exec"
 	"path/filepath"
+	"regexp"
 	"runtime"
 	"strings"
 	"sync"
@@ -17,17 +18,20 @@ import (
 	"text/template"
 )
 
-// testEnv excludes GODEBUG from the environment
-// to prevent its output from breaking tests that
-// are trying to parse other command output.
 func testEnv(cmd *exec.Cmd) *exec.Cmd {
 	if cmd.Env != nil {
 		panic("environment already set")
 	}
 	for _, env := range os.Environ() {
+		// Exclude GODEBUG from the environment to prevent its output
+		// from breaking tests that are trying to parse other command output.
 		if strings.HasPrefix(env, "GODEBUG=") {
 			continue
 		}
+		// Exclude GOTRACEBACK for the same reason.
+		if strings.HasPrefix(env, "GOTRACEBACK=") {
+			continue
+		}
 		cmd.Env = append(cmd.Env, env)
 	}
 	return cmd
@@ -217,6 +221,14 @@ func TestMainGoroutineId(t *testing.T) {
 	}
 }
 
+func TestNoHelperGoroutines(t *testing.T) {
+	output := executeTest(t, noHelperGoroutinesSource, nil)
+	matches := regexp.MustCompile(`goroutine [0-9]+ \[`).FindAllStringSubmatch(output, -1)
+	if len(matches) != 1 || matches[0][0] != "goroutine 1 [" {
+		t.Fatalf("want to see only goroutine 1, see:\n%s", output)
+	}
+}
+
 func TestBreakpoint(t *testing.T) {
 	output := executeTest(t, breakpointSource, nil)
 	want := "runtime.Breakpoint()"
@@ -431,6 +443,22 @@ func main() {
 }
 `
 
+const noHelperGoroutinesSource = `
+package main
+import (
+	"runtime"
+	"time"
+)
+func init() {
+	i := 0
+	runtime.SetFinalizer(&i, func(p *int) {})
+	time.AfterFunc(time.Hour, func() {})
+	panic("oops")
+}
+func main() {
+}
+`
+
 const breakpointSource = `
 package main
 import "runtime"
diff --git a/src/runtime/heapdump.go b/src/runtime/heapdump.go
index 6cbb5f3775..7b4a846195 100644
--- a/src/runtime/heapdump.go
+++ b/src/runtime/heapdump.go
@@ -344,7 +344,7 @@ func dumpgoroutine(gp *g) {
 	dumpint(uint64(gp.goid))
 	dumpint(uint64(gp.gopc))
 	dumpint(uint64(readgstatus(gp)))
-	dumpbool(gp.issystem)
+	dumpbool(isSystemGoroutine(gp))
 	dumpbool(false) // isbackground
 	dumpint(uint64(gp.waitsince))
 	dumpstr(gp.waitreason)
diff --git a/src/runtime/mfinal.go b/src/runtime/mfinal.go
index 28afa0dfab..525aa0955a 100644
--- a/src/runtime/mfinal.go
+++ b/src/runtime/mfinal.go
@@ -102,7 +102,10 @@ func wakefing() *g {
 	return res
 }
 
-var fingCreate uint32
+var (
+	fingCreate  uint32
+	fingRunning bool
+)
 
 func createfing() {
 	// start the finalizer goroutine exactly once
@@ -126,9 +129,7 @@ func runfinq() {
 			gp := getg()
 			fing = gp
 			fingwait = true
-			gp.issystem = true
 			goparkunlock(&finlock, "finalizer wait", traceEvGoBlock)
-			gp.issystem = false
 			continue
 		}
 		unlock(&finlock)
@@ -169,7 +170,9 @@ func runfinq() {
 				default:
 					throw("bad kind in runfinq")
 				}
+				fingRunning = true
 				reflectcall(nil, unsafe.Pointer(f.fn), frame, uint32(framesz), uint32(framesz))
+				fingRunning = false
 
 				// drop finalizer queue references to finalized object
 				f.fn = nil
diff --git a/src/runtime/mgc0.go b/src/runtime/mgc0.go
index bbd786d519..f54d93377d 100644
--- a/src/runtime/mgc0.go
+++ b/src/runtime/mgc0.go
@@ -62,7 +62,6 @@ func clearpools() {
 // bggc holds the state of the backgroundgc.
 func backgroundgc() {
 	bggc.g = getg()
-	bggc.g.issystem = true
 	for {
 		gcwork(0)
 		lock(&bggc.lock)
@@ -73,7 +72,6 @@ func backgroundgc() {
 
 func bgsweep() {
 	sweep.g = getg()
-	getg().issystem = true
 	for {
 		for gosweepone() != ^uintptr(0) {
 			sweep.nbgsweep++
diff --git a/src/runtime/proc.go b/src/runtime/proc.go
index c8f6de1ac8..0411d965a4 100644
--- a/src/runtime/proc.go
+++ b/src/runtime/proc.go
@@ -110,7 +110,6 @@ func init() {
 
 func forcegchelper() {
 	forcegc.g = getg()
-	forcegc.g.issystem = true
 	for {
 		lock(&forcegc.lock)
 		if forcegc.idle != 0 {
diff --git a/src/runtime/proc1.go b/src/runtime/proc1.go
index 70addbffad..1f3ae500fc 100644
--- a/src/runtime/proc1.go
+++ b/src/runtime/proc1.go
@@ -2636,7 +2636,7 @@ func checkdead() {
 	lock(&allglock)
 	for i := 0; i < len(allgs); i++ {
 		gp := allgs[i]
-		if gp.issystem {
+		if isSystemGoroutine(gp) {
 			continue
 		}
 		s := readgstatus(gp)
diff --git a/src/runtime/runtime2.go b/src/runtime/runtime2.go
index e38d11a59d..fab2ccbebf 100644
--- a/src/runtime/runtime2.go
+++ b/src/runtime/runtime2.go
@@ -199,7 +199,6 @@ type g struct {
 	waitsince    int64  // approx time when the g become blocked
 	waitreason   string // if status==gwaiting
 	schedlink    *g
-	issystem     bool // do not output in stack dump, ignore in deadlock detector
 	preempt      bool // preemption signal, duplicates stackguard0 = stackpreempt
 	paniconfault bool // panic (instead of crash) on unexpected fault address
 	preemptscan  bool // preempted g does scan for gc
diff --git a/src/runtime/time.go b/src/runtime/time.go
index 50895ca8ec..6a2cc2136c 100644
--- a/src/runtime/time.go
+++ b/src/runtime/time.go
@@ -153,7 +153,6 @@ func deltimer(t *timer) bool {
 // If addtimer inserts a new earlier event, addtimer1 wakes timerproc early.
 func timerproc() {
 	timers.gp = getg()
-	timers.gp.issystem = true
 	for {
 		lock(&timers.lock)
 		timers.sleeping = false
diff --git a/src/runtime/traceback.go b/src/runtime/traceback.go
index 6c87d7e2e4..8c31c5abad 100644
--- a/src/runtime/traceback.go
+++ b/src/runtime/traceback.go
@@ -39,6 +39,11 @@ var (
 	mstartPC             uintptr
 	rt0_goPC             uintptr
 	sigpanicPC           uintptr
+	runfinqPC            uintptr
+	backgroundgcPC       uintptr
+	bgsweepPC            uintptr
+	forcegchelperPC      uintptr
+	timerprocPC          uintptr
 	systemstack_switchPC uintptr
 
 	externalthreadhandlerp uintptr // initialized elsewhere
@@ -56,6 +61,11 @@ func tracebackinit() {
 	mstartPC = funcPC(mstart)
 	rt0_goPC = funcPC(rt0_go)
 	sigpanicPC = funcPC(sigpanic)
+	runfinqPC = funcPC(runfinq)
+	backgroundgcPC = funcPC(backgroundgc)
+	bgsweepPC = funcPC(bgsweep)
+	forcegchelperPC = funcPC(forcegchelper)
+	timerprocPC = funcPC(timerproc)
 	systemstack_switchPC = funcPC(systemstack_switch)
 }
 
@@ -606,7 +616,7 @@ func tracebackothers(me *g) {
 
 	lock(&allglock)
 	for _, gp := range allgs {
-		if gp == me || gp == g.m.curg || readgstatus(gp) == _Gdead || gp.issystem && level < 2 {
+		if gp == me || gp == g.m.curg || readgstatus(gp) == _Gdead || isSystemGoroutine(gp) && level < 2 {
 			continue
 		}
 		print("\n")
@@ -631,3 +641,14 @@ func topofstack(f *_func) bool {
 		pc == rt0_goPC ||
 		externalthreadhandlerp != 0 && pc == externalthreadhandlerp
 }
+
+// isSystemGoroutine returns true if the goroutine g must be omitted in
+// stack dumps and deadlock detector.
+func isSystemGoroutine(gp *g) bool {
+	pc := gp.startpc
+	return pc == runfinqPC && !fingRunning ||
+		pc == backgroundgcPC ||
+		pc == bgsweepPC ||
+		pc == forcegchelperPC ||
+		pc == timerprocPC
+}