runtime: replace system goroutine whitelist with symbol test

Currently isSystemGoroutine has a hard-coded list of known entry
points into system goroutines. This list is annoying to maintain. For
example, it's missing the ensureSigM goroutine.

Replace it with a check that simply looks for any goroutine with
runtime function as its entry point, with a few exceptions. This also
matches the definition recently added to the trace viewer (CL 81315).

Change-Id: Iaed723d4a6e8c2ffb7c0c48fbac1688b00b30f01
Reviewed-on: https://go-review.googlesource.com/81655
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>

1 files changed, 14 insertions, 7 deletions

diff --git a/src/runtime/traceback.go b/src/runtime/traceback.go
index fd649cbbc6..0fd7ef1987 100644
--- a/src/runtime/traceback.go
+++ b/src/runtime/traceback.go
@@ -990,18 +990,25 @@ func topofstack(f funcInfo, g0 bool) bool {
 		(g0 && f.funcID == funcID_asmcgocall)
 }
 
-// isSystemGoroutine reports whether the goroutine g must be omitted in
-// stack dumps and deadlock detector.
+// isSystemGoroutine reports whether the goroutine g must be omitted
+// in stack dumps and deadlock detector. This is any goroutine that
+// starts at a runtime.* entry point, except for runtime.main and
+// sometimes runtime.runfinq.
 func isSystemGoroutine(gp *g) bool {
+	// Keep this in sync with cmd/trace/trace.go:isSystemGoroutine.
 	f := findfunc(gp.startpc)
 	if !f.valid() {
 		return false
 	}
-	return f.funcID == funcID_runfinq && !fingRunning ||
-		f.funcID == funcID_bgsweep ||
-		f.funcID == funcID_forcegchelper ||
-		f.funcID == funcID_timerproc ||
-		f.funcID == funcID_gcBgMarkWorker
+	if f.funcID == funcID_runtime_main {
+		return false
+	}
+	if f.funcID == funcID_runfinq {
+		// We include the finalizer goroutine if it's calling
+		// back into user code.
+		return !fingRunning
+	}
+	return hasprefix(funcname(f), "runtime.")
 }
 
 // SetCgoTraceback records three C functions to use to gather