commit e58991b3b2282b5761f1a6023a16c803e1c4eb45
author Mathieu Chartier <mathieuc@google.com> Tue Oct 13 07:59:34 2015 -0700
committer Mathieu Chartier <mathieuc@google.com> Tue Oct 13 13:17:50 2015 -0700
tree 5a6fac6c5d3cb6a463463b83b8a34a53b07a8ede
parent fb11bab9bc96ff05dcb12f43abf58df256b7c7aa

Revert "Revert "Unload oat files""

Fixed a race where two threads calling OatFile::Open could both use
dlopen on the host.

Bug: 22720414

This reverts commit 72da5e7461fec3b1e116050f2e6f233efb9c54f3.

Change-Id: I1636045b724944d2a09417527280784967957095

runtime/oat_file.cc

diff --git a/runtime/oat_file.cc b/runtime/oat_file.cc
index 80f017d..daaa195 100644
--- a/runtime/oat_file.cc
+++ b/runtime/oat_file.cc
@@ -122,21 +122,29 @@
   // and for having dex caches arrays in the .bss section.
   Runtime* const runtime = Runtime::Current();
   OatFileManager* const manager = (runtime != nullptr) ? &runtime->GetOatFileManager() : nullptr;
-  if (kUseDlopen &&
-      (kIsTargetBuild ||
-          (kUseDlopenOnHost &&
-           // Manager may be null if we are running without a runtime.
-           manager != nullptr &&
-           manager->FindOpenedOatFileFromOatLocation(location) == nullptr)) &&
-      executable) {
-    // Try to use dlopen. This may fail for various reasons, outlined below. We try dlopen, as
-    // this will register the oat file with the linker and allows libunwind to find our info.
-    ret.reset(OpenDlopen(filename, location, requested_base, abs_dex_location, error_msg));
-    if (ret.get() != nullptr) {
-      return ret.release();
+  if (kUseDlopen && executable) {
+    bool success = kIsTargetBuild;
+    bool reserved_location = false;
+      // Manager may be null if we are running without a runtime.
+    if (!success && kUseDlopenOnHost && manager != nullptr) {
+      // ReserveOatFileLocation returns false if we are not the first caller to register that
+      // location.
+      reserved_location = manager->RegisterOatFileLocation(location);
+      success = reserved_location;
     }
-    if (kPrintDlOpenErrorMessage) {
-      LOG(ERROR) << "Failed to dlopen: " << *error_msg;
+    if (success) {
+      // Try to use dlopen. This may fail for various reasons, outlined below. We try dlopen, as
+      // this will register the oat file with the linker and allows libunwind to find our info.
+      ret.reset(OpenDlopen(filename, location, requested_base, abs_dex_location, error_msg));
+      if (reserved_location) {
+        manager->UnRegisterOatFileLocation(location);
+      }
+      if (ret != nullptr) {
+        return ret.release();
+      }
+      if (kPrintDlOpenErrorMessage) {
+        LOG(ERROR) << "Failed to dlopen: " << *error_msg;
+      }
     }
   }
 
@@ -217,6 +225,10 @@
       is_executable_(is_executable), dlopen_handle_(nullptr),
       secondary_lookup_lock_("OatFile secondary lookup lock", kOatFileSecondaryLookupLock) {
   CHECK(!location_.empty());
+  Runtime* const runtime = Runtime::Current();
+  if (runtime != nullptr && !runtime->IsAotCompiler()) {
+    runtime->GetOatFileManager().RegisterOatFileLocation(location);
+  }
 }
 
 OatFile::~OatFile() {
@@ -224,6 +236,10 @@
   if (dlopen_handle_ != nullptr) {
     dlclose(dlopen_handle_);
   }
+  Runtime* const runtime = Runtime::Current();
+  if (runtime != nullptr && !runtime->IsAotCompiler()) {
+    runtime->GetOatFileManager().UnRegisterOatFileLocation(location_);
+  }
 }
 
 bool OatFile::Dlopen(const std::string& elf_filename, uint8_t* requested_base,