[vm/concurrency/debugger] Fix lock acquisition to avoid deadlocks.

TEST=break_on_function_many_child_isolates_test flaky failures on debug build Fixes #45391 Issue #36097 Change-Id: I075318878f1e4b0f3f921377b0281b785274621e Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/192060 Commit-Queue: Alexander Aprelev <aam@google.com> Reviewed-by: Martin Kustermann <kustermann@google.com>
dart-lang · Mar 19, 2021 · dd9b00f · dd9b00f
1 parent 2c5b320
commit dd9b00f
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Showing 2 changed files with 27 additions and 22 deletions.
diff --git a/runtime/vm/compiler/jit/compiler.cc b/runtime/vm/compiler/jit/compiler.cc
@@ -612,9 +612,11 @@ CodePtr CompileParsedFunctionHelper::Compile(CompilationPipeline* pipeline) {
           // breakpoint.
           if (!result->IsNull()) {
             if (!function.HasOptimizedCode()) {
-              thread()->isolate_group()->ForEachIsolate([&](Isolate* isolate) {
-                isolate->debugger()->NotifyCompilation(function);
-              });
+              thread()->isolate_group()->ForEachIsolate(
+                  [&](Isolate* isolate) {
+                    isolate->debugger()->NotifyCompilation(function);
+                  },
+                  /*at_safepoint=*/true);
             }
           }
 #endif

diff --git a/runtime/vm/runtime_entry.cc b/runtime/vm/runtime_entry.cc
@@ -3011,10 +3011,7 @@ void DeoptimizeAt(Thread* mutator_thread,
   ASSERT(!unoptimized_code.IsNull());
   // The switch to unoptimized code may have already occurred.
   if (function.HasOptimizedCode()) {
-    SafepointWriteRwLocker ml(thread, thread->isolate_group()->program_lock());
-    if (function.HasOptimizedCode()) {
-      function.SwitchToUnoptimizedCode();
-    }
+    function.SwitchToUnoptimizedCode();
   }
 
   if (frame->IsMarkedForLazyDeopt()) {
@@ -3048,23 +3045,29 @@ void DeoptimizeAt(Thread* mutator_thread,
 // Currently checks only that all optimized frames have kDeoptIndex
 // and unoptimized code has the kDeoptAfter.
 void DeoptimizeFunctionsOnStack() {
-  auto isolate_group = IsolateGroup::Current();
+  auto thread = Thread::Current();
+  // Have to grab program_lock before stopping everybody else.
+  SafepointWriteRwLocker ml(thread, thread->isolate_group()->program_lock());
+
+  auto isolate_group = thread->isolate_group();
   isolate_group->RunWithStoppedMutators([&]() {
     Code& optimized_code = Code::Handle();
-    isolate_group->ForEachIsolate([&](Isolate* isolate) {
-      auto mutator_thread = isolate->mutator_thread();
-      DartFrameIterator iterator(
-          mutator_thread, StackFrameIterator::kAllowCrossThreadIteration);
-      StackFrame* frame = iterator.NextFrame();
-      while (frame != nullptr) {
-        optimized_code = frame->LookupDartCode();
-        if (optimized_code.is_optimized() &&
-            !optimized_code.is_force_optimized()) {
-          DeoptimizeAt(mutator_thread, optimized_code, frame);
-        }
-        frame = iterator.NextFrame();
-      }
-    });
+    isolate_group->ForEachIsolate(
+        [&](Isolate* isolate) {
+          auto mutator_thread = isolate->mutator_thread();
+          DartFrameIterator iterator(
+              mutator_thread, StackFrameIterator::kAllowCrossThreadIteration);
+          StackFrame* frame = iterator.NextFrame();
+          while (frame != nullptr) {
+            optimized_code = frame->LookupDartCode();
+            if (optimized_code.is_optimized() &&
+                !optimized_code.is_force_optimized()) {
+              DeoptimizeAt(mutator_thread, optimized_code, frame);
+            }
+            frame = iterator.NextFrame();
+          }
+        },
+        /*at_safepoint=*/true);
   });
 }