3 files changed, 15 insertions, 4 deletions
diff --git a/src/runtime/os_windows.go b/src/runtime/os_windows.go
index 7e9bbd04f2..50f61c1d54 100644
--- a/src/runtime/os_windows.go
+++ b/src/runtime/os_windows.go
@@ -1298,7 +1298,7 @@ func preemptM(mp *m) {
 	// Does it want a preemption and is it safe to preempt?
 	gp := gFromSP(mp, c.sp())
 	if gp != nil && wantAsyncPreempt(gp) {
-		if ok, newpc := isAsyncSafePoint(gp, c.ip(), c.sp(), c.lr()); ok {
+		if ok, newpc := isAsyncSafePoint(gp, c.ip(), c.sp(), c.lr(), panicking.Load() != 0); ok {
 			// Inject call to asyncPreempt
 			targetPC := abi.FuncPCABI0(asyncPreempt)
 			switch GOARCH {
diff --git a/src/runtime/preempt.go b/src/runtime/preempt.go
index 82d85cd707..aedf7f3ff5 100644
--- a/src/runtime/preempt.go
+++ b/src/runtime/preempt.go
@@ -359,7 +359,11 @@ func wantAsyncPreempt(gp *g) bool {
 // In some cases the PC is safe for asynchronous preemption but it
 // also needs to adjust the resumption PC. The new PC is returned in
 // the second result.
-func isAsyncSafePoint(gp *g, pc, sp, lr uintptr) (bool, uintptr) {
+//
+// If noResume is true, we know we're not going to resume execution
+// on this goroutine (as we're crashing), and thus we can preempt
+// more aggressively.
+func isAsyncSafePoint(gp *g, pc, sp, lr uintptr, noResume bool) (bool, uintptr) {
 	mp := gp.m
 
 	// Only user Gs can have safe-points. We check this first
@@ -370,7 +374,7 @@ func isAsyncSafePoint(gp *g, pc, sp, lr uintptr) (bool, uintptr) {
 	}
 
 	// Check M state.
-	if mp.p == 0 || !canPreemptM(mp) {
+	if mp.p == 0 || (!canPreemptM(mp) && !noResume) {
 		return false, 0
 	}
 
@@ -385,6 +389,13 @@ func isAsyncSafePoint(gp *g, pc, sp, lr uintptr) (bool, uintptr) {
 		// Not Go code.
 		return false, 0
 	}
+	if noResume && f.flag&abi.FuncFlagAsm == 0 {
+		// We're not going to resume execution and not going to scan the
+		// stack for GC, so we don't care whether it is a safe point, and
+		// also don't care the resumption PC.
+		// TODO: maybe we can preempt non-SPWRITE assembly functions?
+		return true, pc
+	}
 	if (GOARCH == "mips" || GOARCH == "mipsle" || GOARCH == "mips64" || GOARCH == "mips64le") && lr == pc+8 && funcspdelta(f, pc) == 0 {
 		// We probably stopped at a half-executed CALL instruction,
 		// where the LR is updated but the PC has not. If we preempt
diff --git a/src/runtime/signal_unix.go b/src/runtime/signal_unix.go
index 84391d58ed..78e71c9086 100644
--- a/src/runtime/signal_unix.go
+++ b/src/runtime/signal_unix.go
@@ -342,7 +342,7 @@ func doSigPreempt(gp *g, ctxt *sigctxt) {
 	// Check if this G wants to be preempted and is safe to
 	// preempt.
 	if wantAsyncPreempt(gp) {
-		if ok, newpc := isAsyncSafePoint(gp, ctxt.sigpc(), ctxt.sigsp(), ctxt.siglr()); ok {
+		if ok, newpc := isAsyncSafePoint(gp, ctxt.sigpc(), ctxt.sigsp(), ctxt.siglr(), panicking.Load() != 0); ok {
 			// Adjust the PC and inject a call to asyncPreempt.
 			ctxt.pushCall(abi.FuncPCABI0(asyncPreempt), newpc)
 		}