Shard classloader classes lock

Used to guard adding and removing classes.

Previously we used the class linker classes lock, but this had
a deadlock issue since the reference processor may need to acquire
the lock to mark the classes of a class loader. Another thread could
be blocked trying to access weak globals while also holding the
class linker classes lock.

Bug: 27946564

(cherry picked from commit 1609e3a42051769f4a8be3b6731e7bb2f828b3bb)

Change-Id: Ic5cfe573c4e6822d49ad0862ffdd9d036e439a96

1 files changed, 0 insertions, 1 deletions

diff --git a/runtime/mirror/class_loader-inl.h b/runtime/mirror/class_loader-inl.h
index 84fa80f023..cc910b035a 100644
--- a/runtime/mirror/class_loader-inl.h
+++ b/runtime/mirror/class_loader-inl.h
@@ -34,7 +34,6 @@ inline void ClassLoader::VisitReferences(mirror::Class* klass, const Visitor& vi
   VisitInstanceFieldsReferences<kVerifyFlags, kReadBarrierOption>(klass, visitor);
   if (kVisitClasses) {
     // Visit classes loaded after.
-    ReaderMutexLock mu(Thread::Current(), *Locks::classlinker_classes_lock_);
     ClassTable* const class_table = GetClassTable();
     if (class_table != nullptr) {
       class_table->VisitRoots(visitor);