Suspend all threads when doing hook stuffs to prevent crashes caused by GC

Bridge/src/main/java/com/elderdrivers/riru/xposed/Main.java

@@ -125,4 +125,8 @@ public class Main implements KeepAll {
     public static native void reopenFilesAfterForkNative();
 
     public static native void deoptMethodNative(Object object);
+
+    public static native long suspendAllThreads();
+
+    public static native void resumeAllThreads(long obj);
 }

Bridge/src/main/java/com/elderdrivers/riru/xposed/core/HookMain.java

@@ -1,5 +1,6 @@
 package com.elderdrivers.riru.xposed.core;
 
+import com.elderdrivers.riru.xposed.Main;
 import com.elderdrivers.riru.xposed.entry.hooker.OnePlusWorkAroundHooker;
 import com.elderdrivers.riru.xposed.util.Utils;
 
@@ -111,8 +112,13 @@ public class HookMain {
         if (backup != null) {
             HookMethodResolver.resolveMethod(hook, backup);
         }
-        if (!backupAndHookNative(target, hook, backup)) {
+        long obj = Main.suspendAllThreads();
-            throw new RuntimeException("Failed to hook " + target + " with " + hook);
+        try {
+            if (!backupAndHookNative(target, hook, backup)) {
+                throw new RuntimeException("Failed to hook " + target + " with " + hook);
+            }
+        } finally {
+            Main.resumeAllThreads(obj);
         }
     }
 

Core/jni/main/java_hook/java_hook.cpp

@@ -20,13 +20,13 @@ jobject gInjectDexClassLoader;
 
 static bool isInited = false;
 
-static FileDescriptorTable* gClosedFdTable = nullptr;
+static FileDescriptorTable *gClosedFdTable = nullptr;
 
-void closeFilesBeforeForkNative(JNIEnv*, jclass) {
+void closeFilesBeforeForkNative(JNIEnv *, jclass) {
     gClosedFdTable = FileDescriptorTable::Create();
 }
 
-void reopenFilesAfterForkNative(JNIEnv*, jclass) {
+void reopenFilesAfterForkNative(JNIEnv *, jclass) {
     if (!gClosedFdTable) {
         LOGE("gClosedFdTable is null when reopening files");
         return;
@@ -36,6 +36,22 @@ void reopenFilesAfterForkNative(JNIEnv*, jclass) {
     gClosedFdTable = nullptr;
 }
 
+jlong suspendAllThreads(JNIEnv *, jclass) {
+    if (!suspendAll) {
+        return 0;
+    }
+    ScopedSuspendAll *suspendAllObj = (ScopedSuspendAll *) malloc(sizeof(ScopedSuspendAll));
+    suspendAll(suspendAllObj, "edxp_stop_gc", false);
+    return reinterpret_cast<jlong>(suspendAllObj);
+}
+
+void resumeAllThreads(JNIEnv *, jclass, jlong obj) {
+    if (!resumeAll) {
+        return;
+    }
+    resumeAll(reinterpret_cast<ScopedSuspendAll *>(obj));
+}
+
 static JNINativeMethod hookMethods[] = {
         {
                 "init",
@@ -58,16 +74,22 @@ static JNINativeMethod hookMethods[] = {
                 (void *) Java_lab_galaxy_yahfa_HookMain_ensureMethodCached
         },
         {
-                "getInstallerPkgName", "()Ljava/lang/String;", (void *)get_installer_pkg_name
+                "getInstallerPkgName", "()Ljava/lang/String;", (void *) get_installer_pkg_name
         },
         {
-                "closeFilesBeforeForkNative", "()V", (void *)closeFilesBeforeForkNative
+                "closeFilesBeforeForkNative", "()V", (void *) closeFilesBeforeForkNative
         },
         {
-                "reopenFilesAfterForkNative", "()V", (void *)reopenFilesAfterForkNative
+                "reopenFilesAfterForkNative", "()V", (void *) reopenFilesAfterForkNative
         },
         {
-                "deoptMethodNative", "(Ljava/lang/Object;)V", (void *)deoptimize_method
+                "deoptMethodNative", "(Ljava/lang/Object;)V", (void *) deoptimize_method
+        },
+        {
+                "suspendAllThreads", "()J", (void *) suspendAllThreads
+        },
+        {
+                "resumeAllThreads", "(J)V", (void *) resumeAllThreads
         }
 };
 
@@ -106,7 +128,7 @@ void loadDexAndInit(JNIEnv *env, const char *dexPath) {
     jclass entry_class = findClassFromLoader(env, myClassLoader, ENTRY_CLASS_NAME);
     if (NULL != entry_class) {
         LOGD("HookEntry Class %p", entry_class);
-        env->RegisterNatives(entry_class, hookMethods, 8);
+        env->RegisterNatives(entry_class, hookMethods, 10);
         isInited = true;
         LOGD("RegisterNatives succeed for HookEntry.");
     } else {

Core/jni/main/native_hook/native_hook.cpp

@@ -212,6 +212,19 @@ void hookRuntime(int api_level, void *artHandle, void (*hookFun)(void *, void *,
     }
 }
 
+void (*suspendAll)(ScopedSuspendAll*, const char*, bool) = nullptr;
+void (*resumeAll)(ScopedSuspendAll*) = nullptr;
+
+void getSuspendSyms(int api_level, void *artHandle, void (*hookFun)(void *, void *, void **)) {
+    if (api_level < ANDROID_N) {
+        return;
+    }
+    suspendAll = reinterpret_cast<void (*)(ScopedSuspendAll*,const char*, bool)>(dlsym(artHandle,
+                                                        "_ZN3art16ScopedSuspendAllC2EPKcb"));
+    resumeAll = reinterpret_cast<void (*)(ScopedSuspendAll*)>(dlsym(artHandle,
+                                                            "_ZN3art16ScopedSuspendAllD2Ev"));
+}
+
 void install_inline_hooks() {
     if (inlineHooksInstalled) {
         LOGI("inline hooks installed, skip");
@@ -243,6 +256,7 @@ void install_inline_hooks() {
     }
     hookRuntime(api_level, artHandle, hookFun);
     hookInstrumentation(api_level, artHandle, hookFun);
+    getSuspendSyms(api_level, artHandle, hookFun);
     hookIsInSamePackage(api_level, artHandle, hookFun);
     if (disableHiddenAPIPolicyImpl(api_level, artHandle, hookFun)) {
         LOGI("disableHiddenAPIPolicyImpl done.");

Core/jni/main/native_hook/native_hook.h

@@ -19,6 +19,13 @@ static constexpr const char *kLibWhalePath = "/system/lib/libwhale.so";
     static ret (*old_##func)(__VA_ARGS__); \
     static ret new_##func(__VA_ARGS__)
 
+class ScopedSuspendAll {
+};
+
+extern void (*suspendAll)(ScopedSuspendAll *, const char *, bool);
+
+extern void (*resumeAll)(ScopedSuspendAll *);
+
 void install_inline_hooks();
 
 void deoptimize_method(JNIEnv *env, jclass clazz, jobject method);