diff --git a/src/runtime/os3_plan9.go b/src/runtime/os3_plan9.go
index b6ee98cab6..c5dc23de8b 100644
--- a/src/runtime/os3_plan9.go
+++ b/src/runtime/os3_plan9.go
@@ -100,7 +100,7 @@ func sighandler(_ureg *ureg, note *byte, gp *g) int {
 		if usesLR {
 			c.setpc(funcPC(sigpanictramp))
 		} else {
-			c.setpc(funcPC(sigpanic))
+			c.setpc(funcPC(sigpanic0))
 		}
 		return _NCONT
 	}
diff --git a/src/runtime/signal_windows.go b/src/runtime/signal_windows.go
index 63158f0bc4..f2ce24d735 100644
--- a/src/runtime/signal_windows.go
+++ b/src/runtime/signal_windows.go
@@ -145,7 +145,7 @@ func exceptionhandler(info *exceptionrecord, r *context, gp *g) int32 {
 			*((*uintptr)(sp)) = r.ip()
 		}
 	}
-	r.set_ip(funcPC(sigpanic))
+	r.set_ip(funcPC(sigpanic0))
 	return _EXCEPTION_CONTINUE_EXECUTION
 }
 
diff --git a/src/runtime/stubs.go b/src/runtime/stubs.go
index f11ec539df..f635d942e4 100644
--- a/src/runtime/stubs.go
+++ b/src/runtime/stubs.go
@@ -394,8 +394,10 @@ func duffcopy()
 // Called from linker-generated .initarray; declared for go vet; do NOT call from Go.
 func addmoduledata()
 
-// Injected by the signal handler for panicking signals. On many platforms it just
-// jumps to sigpanic.
+// Injected by the signal handler for panicking signals.
+// Initializes any registers that have fixed meaning at calls but
+// are scratch in bodies and calls sigpanic.
+// On many platforms it just jumps to sigpanic.
 func sigpanic0()
 
 // intArgRegs is used by the various register assignment