diff --git a/src/runtime/proc.go b/src/runtime/proc.go
index 401dcd0a11..6d8fde4349 100644
--- a/src/runtime/proc.go
+++ b/src/runtime/proc.go
@@ -267,6 +267,10 @@ func main() {
 		// has a main, but it is not executed.
 		return
 	}
+
+println("oops")
+	oops()
+
 	fn := main_main // make an indirect call, as the linker doesn't know the address of the main package when laying down the runtime
 	fn()
 	if raceenabled {
@@ -7079,3 +7083,14 @@ func doInit1(t *initTask) {
 		t.state = 2 // initialization done
 	}
 }
+
+//go:noinline
+func oops() {
+	oopssys()
+}
+
+//go:systemstack
+//go:noinline
+func oopssys() {
+	println("onsys")
+}
% 

oops
fatal error: attempt to execute system stack code on user stack

goroutine 1 gp=0x140000021c0 m=0 mp=0x100e67620 [running]:
runtime.throw({0x100c18075?, 0x100a7ee40?})
	/Users/rsc/go/src/runtime/panic.go:1021 +0x40 fp=0x14000131f10 sp=0x14000131ee0 pc=0x100a7c510
runtime.morestackc()
	/Users/rsc/go/src/runtime/stack.go:1296 +0x1c fp=0x14000131f30 sp=0x14000131f10 pc=0x100ab3a4c
runtime.oopssys()
	/Users/rsc/go/src/runtime/proc.go:7094 +0x44 fp=0x14000131f30 sp=0x14000131f30 pc=0x100a8ebd4
runtime.main()
	/Users/rsc/go/src/runtime/proc.go:272 +0x294 fp=0x14000131fc0 sp=0x14000131f30 pc=0x100a7ee44
runtime.main()
	/Users/rsc/go/src/runtime/proc.go:272 +0x294 fp=0x14000132050 sp=0x14000131fc0 pc=0x100a7ee44
runtime: g 1: unexpected return pc for runtime.main called from 0x14000131fb0