[wasm][stack-switching] Throw on re-entrant suspender

Throw a wasm trap when trying to re-enter a suspender that is active or
suspended.

R=ahaas@chromium.org

Bug: v8:12191
Change-Id: Ic448a15db29de14fb8d6bb8408af8fbaae82a2b4
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3716481Reviewed-by: Andreas Haas <ahaas@chromium.org>
Commit-Queue: Thibaud Michaud <thibaudm@chromium.org>
Cr-Commit-Position: refs/heads/main@{#81326}

src/builtins/x64/builtins-x64.cc

@@ -3017,7 +3017,10 @@ void AllocateContinuation(MacroAssembler* masm, Register function_data,
   __ Push(wasm_instance);
   __ Push(function_data);
   __ Push(suspender);  // Argument.
-  __ Move(kContextRegister, Smi::zero());
+  __ LoadAnyTaggedField(
+      kContextRegister,
+      MemOperand(wasm_instance, wasm::ObjectAccess::ToTagged(
+                                    WasmInstanceObject::kNativeContextOffset)));
   __ CallRuntime(Runtime::kWasmAllocateContinuation);
   __ Pop(function_data);
   __ Pop(wasm_instance);
@@ -3228,7 +3231,7 @@ void GenericJSToWasmWrapperHelper(MacroAssembler* masm, bool stack_switch) {
     __ LoadRoot(active_continuation, RootIndex::kActiveContinuation);
     SaveState(masm, active_continuation, rcx, &suspend);
     AllocateContinuation(masm, function_data, wasm_instance);
-    Register target_continuation = rax; /* fixed */
+    Register target_continuation = rax;  // fixed
     // Save the old stack's rbp in r9, and use it to access the parameters in
     // the parent frame.
     // We also distribute the spill slots across the two stacks as needed by

src/common/message-template.h

@@ -650,6 +650,7 @@ namespace internal {
   T(WasmTrapStringOffsetOutOfBounds, "string offset out of bounds")            \
   T(WasmTrapStringIsolatedSurrogate,                                           \
     "Failed to encode string as UTF-8: contains unpaired surrogate")           \
+  T(WasmTrapReentrantSuspender, "re-entering an active/suspended suspender")   \
   T(WasmExceptionError, "wasm exception")                                      \
   /* Asm.js validation related */                                              \
   T(AsmJsInvalid, "Invalid asm.js: %")                                         \

src/runtime/runtime-wasm.cc

@@ -798,6 +798,11 @@ RUNTIME_FUNCTION(Runtime_WasmAllocateContinuation) {
   HandleScope scope(isolate);
   Handle<WasmSuspenderObject> suspender = args.at<WasmSuspenderObject>(0);
 
+  if (suspender->state() != WasmSuspenderObject::kInactive) {
+    return ThrowWasmError(isolate,
+                          MessageTemplate::kWasmTrapReentrantSuspender);
+  }
+
   // Update the continuation state.
   auto parent = handle(WasmContinuationObject::cast(
                            isolate->root(RootIndex::kActiveContinuation)),

test/mjsunit/wasm/stack-switching.js

@@ -323,3 +323,44 @@ load("test/mjsunit/wasm/wasm-module-builder.js");
   let combined_promise = wrapped_export();
   assertPromiseResult(combined_promise, v => assertEquals(v, 42));
 })();
+
+(function TestReenterActiveSuspenderFails() {
+  print(arguments.callee.name);
+  let builder = new WasmModuleBuilder();
+  let import_index = builder.addImport("m", "i", kSig_v_v);
+  builder.addFunction("test", kSig_i_v)
+      .addBody([
+          kExprCallFunction, import_index,
+          kExprI32Const, 0
+          ]).exportFunc();
+  let wrapped_export;
+  function js_import() {
+    wrapped_export(); // Re-enter the same wrapped export.
+  }
+  let instance = builder.instantiate({m: {i: js_import}});
+  let suspender = new WebAssembly.Suspender();
+  wrapped_export = suspender.returnPromiseOnSuspend(instance.exports.test);
+  assertThrows(wrapped_export, WebAssembly.RuntimeError,
+      /re-entering an active\/suspended suspender/);
+})();
+
+(function TestReenterSuspendedSuspenderFails() {
+  print(arguments.callee.name);
+  let builder = new WasmModuleBuilder();
+  let import_index = builder.addImport("m", "i", kSig_v_v);
+  builder.addFunction("test", kSig_i_v)
+      .addBody([
+          kExprCallFunction, import_index,
+          kExprI32Const, 0
+          ]).exportFunc();
+  function js_import() {
+    return Promise.resolve(0);
+  }
+  let instance = builder.instantiate({m: {i: js_import}});
+  let suspender = new WebAssembly.Suspender();
+  let wrapped_export = suspender.returnPromiseOnSuspend(instance.exports.test);
+  let promise1 = wrapped_export();
+  // Re-enter the suspender before resolving the promise.
+  assertThrows(wrapped_export, WebAssembly.RuntimeError,
+      /re-entering an active\/suspended suspender/);
+})();