From 9e726e874580f1e8b2e0bfa63d2e9a3ac911cd1c Mon Sep 17 00:00:00 2001
From: Alex Light <allight@google.com>
Date: Mon, 6 Jun 2016 10:45:28 -0700
Subject: Revert "Revert some flaky unloading"

This reverts commit 73ad16e0193866d36dbd4088ac77fa5d4ceec334.

With this code it is possible that during testing we will race the
final shutdown of some threads (i.e. returning to thread_start after
signaling thread has been finished) with the unloading of libart.so by
libnativehelper. This could cause crashes. By ensuring that libart.so
code is not unloaded in libnativehelper we fix the issue with this
patch.

Bug: 28406866

Change-Id: Ic67118c2a4e743941402b17b6bbfe4cce441f68f
---
 runtime/java_vm_ext.cc | 31 +++++++++++++++++--------------
 1 file changed, 17 insertions(+), 14 deletions(-)

(limited to 'runtime/java_vm_ext.cc')

diff --git a/runtime/java_vm_ext.cc b/runtime/java_vm_ext.cc
index d983a9fa19..c2164126e1 100644
--- a/runtime/java_vm_ext.cc
+++ b/runtime/java_vm_ext.cc
@@ -74,6 +74,10 @@ class SharedLibrary {
     if (self != nullptr) {
       self->GetJniEnv()->DeleteWeakGlobalRef(class_loader_);
     }
+
+    if (!needs_native_bridge_) {
+      android::CloseNativeLibrary(handle_);
+    }
   }
 
   jweak GetClassLoader() const {
@@ -271,8 +275,7 @@ class Libraries {
       REQUIRES(!Locks::jni_libraries_lock_)
       SHARED_REQUIRES(Locks::mutator_lock_) {
     ScopedObjectAccessUnchecked soa(Thread::Current());
-    typedef void (*JNI_OnUnloadFn)(JavaVM*, void*);
-    std::vector<JNI_OnUnloadFn> unload_functions;
+    std::vector<SharedLibrary*> unload_libraries;
     {
       MutexLock mu(soa.Self(), *Locks::jni_libraries_lock_);
       for (auto it = libraries_.begin(); it != libraries_.end(); ) {
@@ -283,15 +286,7 @@ class Libraries {
         // the native libraries of the boot class loader.
         if (class_loader != nullptr &&
             soa.Self()->IsJWeakCleared(class_loader)) {
-          void* const sym = library->FindSymbol("JNI_OnUnload", nullptr);
-          if (sym == nullptr) {
-            VLOG(jni) << "[No JNI_OnUnload found in \"" << library->GetPath() << "\"]";
-          } else {
-            VLOG(jni) << "[JNI_OnUnload found for \"" << library->GetPath() << "\"]";
-            JNI_OnUnloadFn jni_on_unload = reinterpret_cast<JNI_OnUnloadFn>(sym);
-            unload_functions.push_back(jni_on_unload);
-          }
-          delete library;
+          unload_libraries.push_back(library);
           it = libraries_.erase(it);
         } else {
           ++it;
@@ -299,9 +294,17 @@ class Libraries {
       }
     }
     // Do this without holding the jni libraries lock to prevent possible deadlocks.
-    for (JNI_OnUnloadFn fn : unload_functions) {
-      VLOG(jni) << "Calling JNI_OnUnload";
-      (*fn)(soa.Vm(), nullptr);
+    typedef void (*JNI_OnUnloadFn)(JavaVM*, void*);
+    for (auto library : unload_libraries) {
+      void* const sym = library->FindSymbol("JNI_OnUnload", nullptr);
+      if (sym == nullptr) {
+        VLOG(jni) << "[No JNI_OnUnload found in \"" << library->GetPath() << "\"]";
+      } else {
+        VLOG(jni) << "[JNI_OnUnload found for \"" << library->GetPath() << "\"]: Calling...";
+        JNI_OnUnloadFn jni_on_unload = reinterpret_cast<JNI_OnUnloadFn>(sym);
+        jni_on_unload(soa.Vm(), nullptr);
+      }
+      delete library;
     }
   }
 
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