ART: Remove suspension from AttachAgent

It conflicts with calls later. Every plugin needs to do local
protections for itself.

Follow-up to commit ad2dc875ce29c3fafc1129a2a25184df28b66a10.

Bug: 31682382
Bug: 34275017
Test: m test-art-host-run-test-909-attach-agent
Change-Id: Ib698d880feb774a00c819ef14c27a48501ca1f13

1 files changed, 2 insertions, 5 deletions

diff --git a/runtime/runtime.cc b/runtime/runtime.cc
index df5fc5ce8a..55e1852c0c 100644
--- a/runtime/runtime.cc
+++ b/runtime/runtime.cc
@@ -1384,11 +1384,6 @@ static bool EnsureJvmtiPlugin(Runtime* runtime,
 
   Plugin new_plugin = Plugin::Create(plugin_name);
 
-  // Suspend all threads to protect ourself somewhat.
-  Thread* self = Thread::Current();
-  ScopedObjectAccess soa(self);      // Now we know we have the shared lock.
-  ScopedThreadSuspension sts(self, art::kWaitingForDebuggerToAttach);
-  ScopedSuspendAll ssa("EnsureJvmtiPlugin");
   if (!new_plugin.Load(error_msg)) {
     return false;
   }
@@ -2235,6 +2230,8 @@ void Runtime::AddSystemWeakHolder(gc::AbstractSystemWeakHolder* holder) {
   gc::ScopedGCCriticalSection gcs(Thread::Current(),
                                   gc::kGcCauseAddRemoveSystemWeakHolder,
                                   gc::kCollectorTypeAddRemoveSystemWeakHolder);
+  // Note: The ScopedGCCriticalSection also ensures that the rest of the function is in
+  //       a critical section.
   system_weak_holders_.push_back(holder);
 }