[0.81] Implement mechanism to prevent ShadowTree commit exhaustion (#52736)

* Implement mechanism to prevent ShadowTree commit exhaustion (#52645) Summary: Pull Request resolved: https://github.com/facebook/react-native/pull/52645 Changelog: [internal] This add a new feature flag to test a fix for https://github.com/facebook/react-native/issues/51870 Reviewed By: cortinico, sammy-SC Differential Revision: D78418504 fbshipit-source-id: 2792026b6936393d196fd1e3162f8b2c61a38ed6 * Fix incorrect locking and attempts check in ShadowTree experiment (#52681) Summary: Pull Request resolved: https://github.com/facebook/react-native/pull/52681 Changelog: [internal] In the original change I made in D78418504 / https://github.com/facebook/react-native/pull/52645 I made 2 mistakes: 1. Used a lock that would try to re-lock on itself without it being recursive (which would cause a deadlock). I didn't see that because when testing I didn't hit the case where we'd exhaust the options. 2. The `attemps` variable wasn't incremented, so we never left the loop in case of exhaustion. This propagates a flag to `tryCommit` to indicate we've already locked on the commitMutex_ so we don't need to lock again in that case and increases the counter, fixing the issue. Reviewed By: cortinico Differential Revision: D78497509 fbshipit-source-id: 546ccd0c84aed5416ce1aef47d79419b4fe06f66 * Rollout `preventShadowTreeCommitExhaustionWithLocking` in experimental (#52709) Summary: Pull Request resolved: https://github.com/facebook/react-native/pull/52709 We want to make user for folks in OSS to try `preventShadowTreeCommitExhaustionWithLocking`. Therefore I'm updating the OSS release channel for this flag to experimental. Changelog: [Internal] [Changed] - Rollout `preventShadowTreeCommitExhaustionWithLocking` in experimental Reviewed By: rubennorte Differential Revision: D78558655 fbshipit-source-id: 02a9d216c7b2f8f7bdc1340213f82b70c5692dc7 --------- Co-authored-by: Rubén Norte <rubennorte@meta.com>
2025-11-01 09:14:26 +00:00 · 2025-07-21 15:31:19 +01:00
parent d61decce15
commit dd12edf35f
24 changed files with 194 additions and 48 deletions
@@ -4,7 +4,7 @@
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 *
- * @generated SignedSource<<a4a7c66f4603fc6a56018aba12c942ee>>
+ * @generated SignedSource<<f5f8c15a68610c9453d4085626effee2>>
 */

 /**
@@ -312,6 +312,12 @@ public object ReactNativeFeatureFlags {
  @JvmStatic
  public fun preparedTextCacheSize(): Double = accessor.preparedTextCacheSize()

+  /**
+   * Enables a new mechanism in ShadowTree to prevent problems caused by multiple threads trying to commit concurrently. If a thread tries to commit a few times unsuccessfully, it will acquire a lock and try again.
+   */
+  @JvmStatic
+  public fun preventShadowTreeCommitExhaustionWithLocking(): Boolean = accessor.preventShadowTreeCommitExhaustionWithLocking()
+
  /**
   * Enables storing js caller stack when creating promise in native module. This is useful in case of Promise rejection and tracing the cause.
   */
@@ -4,7 +4,7 @@
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 *
- * @generated SignedSource<<9b6d83d6ea0acbc13bce19d869699079>>
+ * @generated SignedSource<<773ddcede573164ba82db671341ddc3f>>
 */

 /**
@@ -67,6 +67,7 @@ internal class ReactNativeFeatureFlagsCxxAccessor : ReactNativeFeatureFlagsAcces
  private var fuseboxNetworkInspectionEnabledCache: Boolean? = null
  private var hideOffscreenVirtualViewsOnIOSCache: Boolean? = null
  private var preparedTextCacheSizeCache: Double? = null
+  private var preventShadowTreeCommitExhaustionWithLockingCache: Boolean? = null
  private var traceTurboModulePromiseRejectionsOnAndroidCache: Boolean? = null
  private var updateRuntimeShadowNodeReferencesOnCommitCache: Boolean? = null
  private var useAlwaysAvailableJSErrorHandlingCache: Boolean? = null
@@ -502,6 +503,15 @@ internal class ReactNativeFeatureFlagsCxxAccessor : ReactNativeFeatureFlagsAcces
    return cached
  }

+  override fun preventShadowTreeCommitExhaustionWithLocking(): Boolean {
+    var cached = preventShadowTreeCommitExhaustionWithLockingCache
+    if (cached == null) {
+      cached = ReactNativeFeatureFlagsCxxInterop.preventShadowTreeCommitExhaustionWithLocking()
+      preventShadowTreeCommitExhaustionWithLockingCache = cached
+    }
+    return cached
+  }
+
  override fun traceTurboModulePromiseRejectionsOnAndroid(): Boolean {
    var cached = traceTurboModulePromiseRejectionsOnAndroidCache
    if (cached == null) {
@@ -4,7 +4,7 @@
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 *
- * @generated SignedSource<<75760457dea789ab0951d3a22be3341c>>
+ * @generated SignedSource<<96fca46813d841eb7f4d043010513999>>
 */

 /**
@@ -122,6 +122,8 @@ public object ReactNativeFeatureFlagsCxxInterop {

  @DoNotStrip @JvmStatic public external fun preparedTextCacheSize(): Double

+  @DoNotStrip @JvmStatic public external fun preventShadowTreeCommitExhaustionWithLocking(): Boolean
+
  @DoNotStrip @JvmStatic public external fun traceTurboModulePromiseRejectionsOnAndroid(): Boolean

  @DoNotStrip @JvmStatic public external fun updateRuntimeShadowNodeReferencesOnCommit(): Boolean
@@ -4,7 +4,7 @@
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 *
- * @generated SignedSource<<48fa8921cc2947a713974c9926e1d806>>
+ * @generated SignedSource<<8ebd61411e0e0ac8c8b307cf803f1206>>
 */

 /**
@@ -117,6 +117,8 @@ public open class ReactNativeFeatureFlagsDefaults : ReactNativeFeatureFlagsProvi

  override fun preparedTextCacheSize(): Double = 200.0

+  override fun preventShadowTreeCommitExhaustionWithLocking(): Boolean = false
+
  override fun traceTurboModulePromiseRejectionsOnAndroid(): Boolean = false

  override fun updateRuntimeShadowNodeReferencesOnCommit(): Boolean = false
@@ -4,7 +4,7 @@
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 *
- * @generated SignedSource<<356261385b837def94ac5a4ca7ffd05d>>
+ * @generated SignedSource<<a7e62fa950e2716e664e7f6d30d4c941>>
 */

 /**
@@ -71,6 +71,7 @@ internal class ReactNativeFeatureFlagsLocalAccessor : ReactNativeFeatureFlagsAcc
  private var fuseboxNetworkInspectionEnabledCache: Boolean? = null
  private var hideOffscreenVirtualViewsOnIOSCache: Boolean? = null
  private var preparedTextCacheSizeCache: Double? = null
+  private var preventShadowTreeCommitExhaustionWithLockingCache: Boolean? = null
  private var traceTurboModulePromiseRejectionsOnAndroidCache: Boolean? = null
  private var updateRuntimeShadowNodeReferencesOnCommitCache: Boolean? = null
  private var useAlwaysAvailableJSErrorHandlingCache: Boolean? = null
@@ -553,6 +554,16 @@ internal class ReactNativeFeatureFlagsLocalAccessor : ReactNativeFeatureFlagsAcc
    return cached
  }

+  override fun preventShadowTreeCommitExhaustionWithLocking(): Boolean {
+    var cached = preventShadowTreeCommitExhaustionWithLockingCache
+    if (cached == null) {
+      cached = currentProvider.preventShadowTreeCommitExhaustionWithLocking()
+      accessedFeatureFlags.add("preventShadowTreeCommitExhaustionWithLocking")
+      preventShadowTreeCommitExhaustionWithLockingCache = cached
+    }
+    return cached
+  }
+
  override fun traceTurboModulePromiseRejectionsOnAndroid(): Boolean {
    var cached = traceTurboModulePromiseRejectionsOnAndroidCache
    if (cached == null) {
@@ -4,7 +4,7 @@
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 *
- * @generated SignedSource<<c8b19934d19d6b4514a0395edecb1330>>
+ * @generated SignedSource<<93aab733661b558c1701b728c18b3d00>>
 */

 /**
@@ -23,5 +23,5 @@ public open class ReactNativeFeatureFlagsOverrides_RNOSS_Experimental_Android :
  // We could use JNI to get the defaults from C++,
  // but that is more expensive than just duplicating the defaults here.

-
+  override fun preventShadowTreeCommitExhaustionWithLocking(): Boolean = true
 }
@@ -4,7 +4,7 @@
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 *
- * @generated SignedSource<<8abf9bfb81265ae0c840457eb6c199bd>>
+ * @generated SignedSource<<f3b9aa1ed32aa3e013e16d4abb10b9cf>>
 */

 /**
@@ -117,6 +117,8 @@ public interface ReactNativeFeatureFlagsProvider {

  @DoNotStrip public fun preparedTextCacheSize(): Double

+  @DoNotStrip public fun preventShadowTreeCommitExhaustionWithLocking(): Boolean
+
  @DoNotStrip public fun traceTurboModulePromiseRejectionsOnAndroid(): Boolean

  @DoNotStrip public fun updateRuntimeShadowNodeReferencesOnCommit(): Boolean
@@ -4,7 +4,7 @@
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 *
- * @generated SignedSource<<5effd7d4ac8034424144ea68c82b61a7>>
+ * @generated SignedSource<<7fac1c2c0c3ce131442319925e4231dc>>
 */

 /**
@@ -321,6 +321,12 @@ class ReactNativeFeatureFlagsJavaProvider
    return method(javaProvider_);
  }

+  bool preventShadowTreeCommitExhaustionWithLocking() override {
+    static const auto method =
+        getReactNativeFeatureFlagsProviderJavaClass()->getMethod<jboolean()>("preventShadowTreeCommitExhaustionWithLocking");
+    return method(javaProvider_);
+  }
+
  bool traceTurboModulePromiseRejectionsOnAndroid() override {
    static const auto method =
        getReactNativeFeatureFlagsProviderJavaClass()->getMethod<jboolean()>("traceTurboModulePromiseRejectionsOnAndroid");
@@ -626,6 +632,11 @@ double JReactNativeFeatureFlagsCxxInterop::preparedTextCacheSize(
  return ReactNativeFeatureFlags::preparedTextCacheSize();
 }

+bool JReactNativeFeatureFlagsCxxInterop::preventShadowTreeCommitExhaustionWithLocking(
+    facebook::jni::alias_ref<JReactNativeFeatureFlagsCxxInterop> /*unused*/) {
+  return ReactNativeFeatureFlags::preventShadowTreeCommitExhaustionWithLocking();
+}
+
 bool JReactNativeFeatureFlagsCxxInterop::traceTurboModulePromiseRejectionsOnAndroid(
    facebook::jni::alias_ref<JReactNativeFeatureFlagsCxxInterop> /*unused*/) {
  return ReactNativeFeatureFlags::traceTurboModulePromiseRejectionsOnAndroid();
@@ -853,6 +864,9 @@ void JReactNativeFeatureFlagsCxxInterop::registerNatives() {
      makeNativeMethod(
        "preparedTextCacheSize",
        JReactNativeFeatureFlagsCxxInterop::preparedTextCacheSize),
+      makeNativeMethod(
+        "preventShadowTreeCommitExhaustionWithLocking",
+        JReactNativeFeatureFlagsCxxInterop::preventShadowTreeCommitExhaustionWithLocking),
      makeNativeMethod(
        "traceTurboModulePromiseRejectionsOnAndroid",
        JReactNativeFeatureFlagsCxxInterop::traceTurboModulePromiseRejectionsOnAndroid),
@@ -4,7 +4,7 @@
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 *
- * @generated SignedSource<<f7bf09b9287dc649901b99ca3f250c28>>
+ * @generated SignedSource<<07daae0284829d56b7eaa330b1973e02>>
 */

 /**
@@ -171,6 +171,9 @@ class JReactNativeFeatureFlagsCxxInterop
  static double preparedTextCacheSize(
    facebook::jni::alias_ref<JReactNativeFeatureFlagsCxxInterop>);

+  static bool preventShadowTreeCommitExhaustionWithLocking(
+    facebook::jni::alias_ref<JReactNativeFeatureFlagsCxxInterop>);
+
  static bool traceTurboModulePromiseRejectionsOnAndroid(
    facebook::jni::alias_ref<JReactNativeFeatureFlagsCxxInterop>);

@@ -4,7 +4,7 @@
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 *
- * @generated SignedSource<<20c25bf5541e37cd5c918684925726df>>
+ * @generated SignedSource<<0179ba45718903d6fec6dcc19b0e1aaa>>
 */

 /**
@@ -214,6 +214,10 @@ double ReactNativeFeatureFlags::preparedTextCacheSize() {
  return getAccessor().preparedTextCacheSize();
 }

+bool ReactNativeFeatureFlags::preventShadowTreeCommitExhaustionWithLocking() {
+  return getAccessor().preventShadowTreeCommitExhaustionWithLocking();
+}
+
 bool ReactNativeFeatureFlags::traceTurboModulePromiseRejectionsOnAndroid() {
  return getAccessor().traceTurboModulePromiseRejectionsOnAndroid();
 }
@@ -4,7 +4,7 @@
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 *
- * @generated SignedSource<<20809734183aa7bfd7aad9b8d01ea080>>
+ * @generated SignedSource<<5055890d2cb2fb46a940f8308f014f0b>>
 */

 /**
@@ -274,6 +274,11 @@ class ReactNativeFeatureFlags {
   */
  RN_EXPORT static double preparedTextCacheSize();

+  /**
+   * Enables a new mechanism in ShadowTree to prevent problems caused by multiple threads trying to commit concurrently. If a thread tries to commit a few times unsuccessfully, it will acquire a lock and try again.
+   */
+  RN_EXPORT static bool preventShadowTreeCommitExhaustionWithLocking();
+
  /**
   * Enables storing js caller stack when creating promise in native module. This is useful in case of Promise rejection and tracing the cause.
   */
@@ -4,7 +4,7 @@
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 *
- * @generated SignedSource<<59ec29e038344c52eaa10845efc5240b>>
+ * @generated SignedSource<<ea72f787f16b0c96ad745e82067591a9>>
 */

 /**
@@ -875,6 +875,24 @@ double ReactNativeFeatureFlagsAccessor::preparedTextCacheSize() {
  return flagValue.value();
 }

+bool ReactNativeFeatureFlagsAccessor::preventShadowTreeCommitExhaustionWithLocking() {
+  auto flagValue = preventShadowTreeCommitExhaustionWithLocking_.load();
+
+  if (!flagValue.has_value()) {
+    // This block is not exclusive but it is not necessary.
+    // If multiple threads try to initialize the feature flag, we would only
+    // be accessing the provider multiple times but the end state of this
+    // instance and the returned flag value would be the same.
+
+    markFlagAsAccessed(47, "preventShadowTreeCommitExhaustionWithLocking");
+
+    flagValue = currentProvider_->preventShadowTreeCommitExhaustionWithLocking();
+    preventShadowTreeCommitExhaustionWithLocking_ = flagValue;
+  }
+
+  return flagValue.value();
+}
+
 bool ReactNativeFeatureFlagsAccessor::traceTurboModulePromiseRejectionsOnAndroid() {
  auto flagValue = traceTurboModulePromiseRejectionsOnAndroid_.load();

@@ -884,7 +902,7 @@ bool ReactNativeFeatureFlagsAccessor::traceTurboModulePromiseRejectionsOnAndroid
    // be accessing the provider multiple times but the end state of this
    // instance and the returned flag value would be the same.

-    markFlagAsAccessed(47, "traceTurboModulePromiseRejectionsOnAndroid");
+    markFlagAsAccessed(48, "traceTurboModulePromiseRejectionsOnAndroid");

    flagValue = currentProvider_->traceTurboModulePromiseRejectionsOnAndroid();
    traceTurboModulePromiseRejectionsOnAndroid_ = flagValue;
@@ -902,7 +920,7 @@ bool ReactNativeFeatureFlagsAccessor::updateRuntimeShadowNodeReferencesOnCommit(
    // be accessing the provider multiple times but the end state of this
    // instance and the returned flag value would be the same.

-    markFlagAsAccessed(48, "updateRuntimeShadowNodeReferencesOnCommit");
+    markFlagAsAccessed(49, "updateRuntimeShadowNodeReferencesOnCommit");

    flagValue = currentProvider_->updateRuntimeShadowNodeReferencesOnCommit();
    updateRuntimeShadowNodeReferencesOnCommit_ = flagValue;
@@ -920,7 +938,7 @@ bool ReactNativeFeatureFlagsAccessor::useAlwaysAvailableJSErrorHandling() {
    // be accessing the provider multiple times but the end state of this
    // instance and the returned flag value would be the same.

-    markFlagAsAccessed(49, "useAlwaysAvailableJSErrorHandling");
+    markFlagAsAccessed(50, "useAlwaysAvailableJSErrorHandling");

    flagValue = currentProvider_->useAlwaysAvailableJSErrorHandling();
    useAlwaysAvailableJSErrorHandling_ = flagValue;
@@ -938,7 +956,7 @@ bool ReactNativeFeatureFlagsAccessor::useFabricInterop() {
    // be accessing the provider multiple times but the end state of this
    // instance and the returned flag value would be the same.

-    markFlagAsAccessed(50, "useFabricInterop");
+    markFlagAsAccessed(51, "useFabricInterop");

    flagValue = currentProvider_->useFabricInterop();
    useFabricInterop_ = flagValue;
@@ -956,7 +974,7 @@ bool ReactNativeFeatureFlagsAccessor::useNativeViewConfigsInBridgelessMode() {
    // be accessing the provider multiple times but the end state of this
    // instance and the returned flag value would be the same.

-    markFlagAsAccessed(51, "useNativeViewConfigsInBridgelessMode");
+    markFlagAsAccessed(52, "useNativeViewConfigsInBridgelessMode");

    flagValue = currentProvider_->useNativeViewConfigsInBridgelessMode();
    useNativeViewConfigsInBridgelessMode_ = flagValue;
@@ -974,7 +992,7 @@ bool ReactNativeFeatureFlagsAccessor::useOptimizedEventBatchingOnAndroid() {
    // be accessing the provider multiple times but the end state of this
    // instance and the returned flag value would be the same.

-    markFlagAsAccessed(52, "useOptimizedEventBatchingOnAndroid");
+    markFlagAsAccessed(53, "useOptimizedEventBatchingOnAndroid");

    flagValue = currentProvider_->useOptimizedEventBatchingOnAndroid();
    useOptimizedEventBatchingOnAndroid_ = flagValue;
@@ -992,7 +1010,7 @@ bool ReactNativeFeatureFlagsAccessor::useRawPropsJsiValue() {
    // be accessing the provider multiple times but the end state of this
    // instance and the returned flag value would be the same.

-    markFlagAsAccessed(53, "useRawPropsJsiValue");
+    markFlagAsAccessed(54, "useRawPropsJsiValue");

    flagValue = currentProvider_->useRawPropsJsiValue();
    useRawPropsJsiValue_ = flagValue;
@@ -1010,7 +1028,7 @@ bool ReactNativeFeatureFlagsAccessor::useShadowNodeStateOnClone() {
    // be accessing the provider multiple times but the end state of this
    // instance and the returned flag value would be the same.

-    markFlagAsAccessed(54, "useShadowNodeStateOnClone");
+    markFlagAsAccessed(55, "useShadowNodeStateOnClone");

    flagValue = currentProvider_->useShadowNodeStateOnClone();
    useShadowNodeStateOnClone_ = flagValue;
@@ -1028,7 +1046,7 @@ bool ReactNativeFeatureFlagsAccessor::useTurboModuleInterop() {
    // be accessing the provider multiple times but the end state of this
    // instance and the returned flag value would be the same.

-    markFlagAsAccessed(55, "useTurboModuleInterop");
+    markFlagAsAccessed(56, "useTurboModuleInterop");

    flagValue = currentProvider_->useTurboModuleInterop();
    useTurboModuleInterop_ = flagValue;
@@ -1046,7 +1064,7 @@ bool ReactNativeFeatureFlagsAccessor::useTurboModules() {
    // be accessing the provider multiple times but the end state of this
    // instance and the returned flag value would be the same.

-    markFlagAsAccessed(56, "useTurboModules");
+    markFlagAsAccessed(57, "useTurboModules");

    flagValue = currentProvider_->useTurboModules();
    useTurboModules_ = flagValue;
@@ -1064,7 +1082,7 @@ double ReactNativeFeatureFlagsAccessor::virtualViewPrerenderRatio() {
    // be accessing the provider multiple times but the end state of this
    // instance and the returned flag value would be the same.

-    markFlagAsAccessed(57, "virtualViewPrerenderRatio");
+    markFlagAsAccessed(58, "virtualViewPrerenderRatio");

    flagValue = currentProvider_->virtualViewPrerenderRatio();
    virtualViewPrerenderRatio_ = flagValue;
@@ -4,7 +4,7 @@
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 *
- * @generated SignedSource<<043e1a56e7a302fbca38151b5d079616>>
+ * @generated SignedSource<<5ed90d5ed1a03a16f551cd1cf6cbdeb3>>
 */

 /**
@@ -79,6 +79,7 @@ class ReactNativeFeatureFlagsAccessor {
  bool fuseboxNetworkInspectionEnabled();
  bool hideOffscreenVirtualViewsOnIOS();
  double preparedTextCacheSize();
+  bool preventShadowTreeCommitExhaustionWithLocking();
  bool traceTurboModulePromiseRejectionsOnAndroid();
  bool updateRuntimeShadowNodeReferencesOnCommit();
  bool useAlwaysAvailableJSErrorHandling();
@@ -101,7 +102,7 @@ class ReactNativeFeatureFlagsAccessor {
  std::unique_ptr<ReactNativeFeatureFlagsProvider> currentProvider_;
  bool wasOverridden_;

-  std::array<std::atomic<const char*>, 58> accessedFeatureFlags_;
+  std::array<std::atomic<const char*>, 59> accessedFeatureFlags_;

  std::atomic<std::optional<bool>> commonTestFlag_;
  std::atomic<std::optional<bool>> animatedShouldSignalBatch_;
@@ -150,6 +151,7 @@ class ReactNativeFeatureFlagsAccessor {
  std::atomic<std::optional<bool>> fuseboxNetworkInspectionEnabled_;
  std::atomic<std::optional<bool>> hideOffscreenVirtualViewsOnIOS_;
  std::atomic<std::optional<double>> preparedTextCacheSize_;
+  std::atomic<std::optional<bool>> preventShadowTreeCommitExhaustionWithLocking_;
  std::atomic<std::optional<bool>> traceTurboModulePromiseRejectionsOnAndroid_;
  std::atomic<std::optional<bool>> updateRuntimeShadowNodeReferencesOnCommit_;
  std::atomic<std::optional<bool>> useAlwaysAvailableJSErrorHandling_;
@@ -4,7 +4,7 @@
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 *
- * @generated SignedSource<<7b5caffd8f748384aa32ed6e153ee9c1>>
+ * @generated SignedSource<<d9fdce0b92313eff37d7146d25b80d4a>>
 */

 /**
@@ -215,6 +215,10 @@ class ReactNativeFeatureFlagsDefaults : public ReactNativeFeatureFlagsProvider {
    return 200.0;
  }

+  bool preventShadowTreeCommitExhaustionWithLocking() override {
+    return false;
+  }
+
  bool traceTurboModulePromiseRejectionsOnAndroid() override {
    return false;
  }
@@ -4,7 +4,7 @@
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 *
- * @generated SignedSource<<e78150be120e3fdf02f9420abce23bfc>>
+ * @generated SignedSource<<ae01d3b37b41ff2ef7fdc26977954b7e>>
 */

 /**
@@ -468,6 +468,15 @@ class ReactNativeFeatureFlagsDynamicProvider : public ReactNativeFeatureFlagsDef
    return ReactNativeFeatureFlagsDefaults::preparedTextCacheSize();
  }

+  bool preventShadowTreeCommitExhaustionWithLocking() override {
+    auto value = values_["preventShadowTreeCommitExhaustionWithLocking"];
+    if (!value.isNull()) {
+      return value.getBool();
+    }
+
+    return ReactNativeFeatureFlagsDefaults::preventShadowTreeCommitExhaustionWithLocking();
+  }
+
  bool traceTurboModulePromiseRejectionsOnAndroid() override {
    auto value = values_["traceTurboModulePromiseRejectionsOnAndroid"];
    if (!value.isNull()) {
@@ -4,7 +4,7 @@
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 *
- * @generated SignedSource<<1de02178e1be302bb4b19501950b260a>>
+ * @generated SignedSource<<16c5fdf431579bbfd454a28c06f28c41>>
 */

 /**
@@ -27,7 +27,9 @@ class ReactNativeFeatureFlagsOverridesOSSExperimental : public ReactNativeFeatur
 public:
    ReactNativeFeatureFlagsOverridesOSSExperimental() = default;

-
+  bool preventShadowTreeCommitExhaustionWithLocking() override {
+    return true;
+  }
 };

 } // namespace facebook::react
@@ -4,7 +4,7 @@
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 *
- * @generated SignedSource<<bdd21870bf567207ad837eb33ae4ca5b>>
+ * @generated SignedSource<<bf06b42a9dfc43a3bfe4e8e59587ea71>>
 */

 /**
@@ -72,6 +72,7 @@ class ReactNativeFeatureFlagsProvider {
  virtual bool fuseboxNetworkInspectionEnabled() = 0;
  virtual bool hideOffscreenVirtualViewsOnIOS() = 0;
  virtual double preparedTextCacheSize() = 0;
+  virtual bool preventShadowTreeCommitExhaustionWithLocking() = 0;
  virtual bool traceTurboModulePromiseRejectionsOnAndroid() = 0;
  virtual bool updateRuntimeShadowNodeReferencesOnCommit() = 0;
  virtual bool useAlwaysAvailableJSErrorHandling() = 0;
@@ -4,7 +4,7 @@
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 *
- * @generated SignedSource<<aebe2ba2618903a0ac2df06f18df8c75>>
+ * @generated SignedSource<<b6c1cb535484fe2a5ff839ca2a9ece46>>
 */

 /**
@@ -279,6 +279,11 @@ double NativeReactNativeFeatureFlags::preparedTextCacheSize(
  return ReactNativeFeatureFlags::preparedTextCacheSize();
 }

+bool NativeReactNativeFeatureFlags::preventShadowTreeCommitExhaustionWithLocking(
+    jsi::Runtime& /*runtime*/) {
+  return ReactNativeFeatureFlags::preventShadowTreeCommitExhaustionWithLocking();
+}
+
 bool NativeReactNativeFeatureFlags::traceTurboModulePromiseRejectionsOnAndroid(
    jsi::Runtime& /*runtime*/) {
  return ReactNativeFeatureFlags::traceTurboModulePromiseRejectionsOnAndroid();
@@ -4,7 +4,7 @@
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 *
- * @generated SignedSource<<f3336bad491a91abb3af7e8fcd7e5938>>
+ * @generated SignedSource<<03ab35c55476b69046e67235b66533a0>>
 */

 /**
@@ -130,6 +130,8 @@ class NativeReactNativeFeatureFlags

  double preparedTextCacheSize(jsi::Runtime& runtime);

+  bool preventShadowTreeCommitExhaustionWithLocking(jsi::Runtime& runtime);
+
  bool traceTurboModulePromiseRejectionsOnAndroid(jsi::Runtime& runtime);

  bool updateRuntimeShadowNodeReferencesOnCommit(jsi::Runtime& runtime);
@@ -25,6 +25,10 @@ namespace facebook::react {
 using CommitStatus = ShadowTree::CommitStatus;
 using CommitMode = ShadowTree::CommitMode;

+namespace {
+const int MAX_COMMIT_ATTEMPTS_BEFORE_LOCKING = 3;
+}
+
 /*
 * Generates (possibly) a new tree where all nodes with non-obsolete `State`
 * objects. If all `State` objects in the tree are not obsolete for the moment
@@ -241,23 +245,39 @@ CommitStatus ShadowTree::commit(
    const CommitOptions& commitOptions) const {
  [[maybe_unused]] int attempts = 0;

-  while (true) {
-    attempts++;
-
-    auto status = tryCommit(transaction, commitOptions);
-    if (status != CommitStatus::Failed) {
-      return status;
+  if (ReactNativeFeatureFlags::preventShadowTreeCommitExhaustionWithLocking()) {
+    while (attempts < MAX_COMMIT_ATTEMPTS_BEFORE_LOCKING) {
+      auto status = tryCommit(transaction, commitOptions);
+      if (status != CommitStatus::Failed) {
+        return status;
+      }
+      attempts++;
    }

-    // After multiple attempts, we failed to commit the transaction.
-    // Something internally went terribly wrong.
-    react_native_assert(attempts < 1024);
+    {
+      std::unique_lock lock(commitMutex_);
+      return tryCommit(transaction, commitOptions, true);
+    }
+  } else {
+    while (true) {
+      attempts++;
+
+      auto status = tryCommit(transaction, commitOptions);
+      if (status != CommitStatus::Failed) {
+        return status;
+      }
+
+      // After multiple attempts, we failed to commit the transaction.
+      // Something internally went terribly wrong.
+      react_native_assert(attempts < 1024);
+    }
  }
 }

 CommitStatus ShadowTree::tryCommit(
    const ShadowTreeCommitTransaction& transaction,
-    const CommitOptions& commitOptions) const {
+    const CommitOptions& commitOptions,
+    bool hasLocked) const {
  TraceSection s("ShadowTree::commit");

  auto telemetry = TransactionTelemetry{};
@@ -269,7 +289,10 @@ CommitStatus ShadowTree::tryCommit(

  {
    // Reading `currentRevision_` in shared manner.
-    std::shared_lock lock(commitMutex_);
+    std::shared_lock lock(commitMutex_, std::defer_lock);
+    if (!hasLocked) {
+      lock.lock();
+    }
    commitMode = commitMode_;
    oldRevision = currentRevision_;
  }
@@ -310,7 +333,10 @@ CommitStatus ShadowTree::tryCommit(

  {
    // Updating `currentRevision_` in unique manner if it hasn't changed.
-    std::unique_lock lock(commitMutex_);
+    std::unique_lock lock(commitMutex_, std::defer_lock);
+    if (!hasLocked) {
+      lock.lock();
+    }

    if (currentRevision_.number != oldRevision.number) {
      return CommitStatus::Failed;
@@ -111,7 +111,8 @@ class ShadowTree final {
   */
  CommitStatus tryCommit(
      const ShadowTreeCommitTransaction& transaction,
-      const CommitOptions& commitOptions) const;
+      const CommitOptions& commitOptions,
+      bool hasLocked = false) const;

  /*
   * Calls `tryCommit` in a loop until it finishes successfully.
@@ -543,6 +543,17 @@ const definitions: FeatureFlagDefinitions = {
      },
      ossReleaseStage: 'none',
    },
+    preventShadowTreeCommitExhaustionWithLocking: {
+      defaultValue: false,
+      metadata: {
+        dateAdded: '2025-07-14',
+        description:
+          'Enables a new mechanism in ShadowTree to prevent problems caused by multiple threads trying to commit concurrently. If a thread tries to commit a few times unsuccessfully, it will acquire a lock and try again.',
+        expectedReleaseValue: true,
+        purpose: 'experimentation',
+      },
+      ossReleaseStage: 'experimental',
+    },
    traceTurboModulePromiseRejectionsOnAndroid: {
      defaultValue: false,
      metadata: {
@@ -4,7 +4,7 @@
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 *
- * @generated SignedSource<<b75fccb46a36b07c692d890f0659f9a3>>
+ * @generated SignedSource<<595a51e39658c12aab12032f7b928615>>
 * @flow strict
 * @noformat
 */
@@ -98,6 +98,7 @@ export type ReactNativeFeatureFlags = $ReadOnly<{
  fuseboxNetworkInspectionEnabled: Getter<boolean>,
  hideOffscreenVirtualViewsOnIOS: Getter<boolean>,
  preparedTextCacheSize: Getter<number>,
+  preventShadowTreeCommitExhaustionWithLocking: Getter<boolean>,
  traceTurboModulePromiseRejectionsOnAndroid: Getter<boolean>,
  updateRuntimeShadowNodeReferencesOnCommit: Getter<boolean>,
  useAlwaysAvailableJSErrorHandling: Getter<boolean>,
@@ -383,6 +384,10 @@ export const hideOffscreenVirtualViewsOnIOS: Getter<boolean> = createNativeFlagG
 * Number cached PreparedLayouts in TextLayoutManager cache
 */
 export const preparedTextCacheSize: Getter<number> = createNativeFlagGetter('preparedTextCacheSize', 200);
+/**
+ * Enables a new mechanism in ShadowTree to prevent problems caused by multiple threads trying to commit concurrently. If a thread tries to commit a few times unsuccessfully, it will acquire a lock and try again.
+ */
+export const preventShadowTreeCommitExhaustionWithLocking: Getter<boolean> = createNativeFlagGetter('preventShadowTreeCommitExhaustionWithLocking', false);
 /**
 * Enables storing js caller stack when creating promise in native module. This is useful in case of Promise rejection and tracing the cause.
 */
@@ -4,7 +4,7 @@
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 *
- * @generated SignedSource<<55c1f0223345b5680bbdd888a358f210>>
+ * @generated SignedSource<<9d6574da819c190bed0458559c66a089>>
 * @flow strict
 * @noformat
 */
@@ -72,6 +72,7 @@ export interface Spec extends TurboModule {
  +fuseboxNetworkInspectionEnabled?: () => boolean;
  +hideOffscreenVirtualViewsOnIOS?: () => boolean;
  +preparedTextCacheSize?: () => number;
+  +preventShadowTreeCommitExhaustionWithLocking?: () => boolean;
  +traceTurboModulePromiseRejectionsOnAndroid?: () => boolean;
  +updateRuntimeShadowNodeReferencesOnCommit?: () => boolean;
  +useAlwaysAvailableJSErrorHandling?: () => boolean;