Fix shutdown races and move signal blocking into profiler

runtime/vm/profiler_linux.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "platform/globals.h"
 #if defined(TARGET_OS_LINUX)
 
 #include "vm/isolate.h"
 #include "vm/json_stream.h"
 #include "vm/profiler.h"
@@ skipping 37 matching lines @@
     return;
   }
   // Thread owns no profiler locks at this point.
   {
     // Thread owns isolate profiler data mutex.
     ScopedMutex profiler_data_lock(isolate->profiler_data_mutex());
     IsolateProfilerData* profiler_data = isolate->profiler_data();
     if (profiler_data == NULL) {
       return;
     }
+    if (!profiler_data->CanExpire()) {
+      // Descheduled.
+      return;
+    }
 
     uintptr_t stack_lower = 0;
     uintptr_t stack_upper = 0;
     isolate->GetStackBounds(&stack_lower, &stack_upper);
     uintptr_t PC = SignalHandler::GetProgramCounter(mcontext);
     uintptr_t FP = SignalHandler::GetFramePointer(mcontext);
     uintptr_t SP = SignalHandler::GetStackPointer(mcontext);
     int64_t sample_time = OS::GetCurrentTimeMicros();
     profiler_data->SampledAt(sample_time);
     CollectSample(profiler_data, PC, FP, SP, stack_lower, stack_upper);
   }
   // Thread owns no profiler locks at this point.
   // This call will acquire both ProfilerManager::monitor and the
   // isolate's profiler data mutex.
-  ProfilerManager::ScheduleIsolate(isolate);
+  ProfilerManager::ScheduleIsolate(isolate, true);
 }
 
 
 int64_t ProfilerManager::SampleAndRescheduleIsolates(int64_t current_time) {
   if (isolates_size_ == 0) {
     return 0;
   }
   static const int64_t max_time = 0x7fffffffffffffffLL;
   int64_t lowest = max_time;
   intptr_t i = 0;
   while (i < isolates_size_) {
     Isolate* isolate = isolates_[i];
     ScopedMutex isolate_lock(isolate->profiler_data_mutex());
     IsolateProfilerData* profiler_data = isolate->profiler_data();
+    if (profiler_data == NULL) {
+      // Isolate has been shutdown for profiling.
+      RemoveIsolate(i);
+      // Remove moves the last element into i, do not increment i.
+      continue;
+    }
     ASSERT(profiler_data != NULL);
     if (profiler_data->ShouldSample(current_time)) {
       pthread_kill(profiler_data->thread_id(), SIGPROF);
       RemoveIsolate(i);
       // Remove moves the last element into i, do not increment i.
       continue;
     }
     if (profiler_data->CanExpire()) {
       int64_t isolate_time_left =
           profiler_data->TimeUntilExpiration(current_time);
@@ skipping 27 matching lines @@
     int64_t current_time = OS::GetCurrentTimeMicros();
     int64_t next_sample = SampleAndRescheduleIsolates(current_time);
     lock.WaitMicros(next_sample);
   }
 }
 
 
 }  // namespace dart
 
 #endif  // defined(TARGET_OS_LINUX)