Proposals for implementing a scheduler in TSAN

[dorooleg]

Summary

First implementation of thread scheduling algorithms and platforms. The full description of the discussion can be found: https://groups.google.com/forum/#!topic/thread-sanitizer/c32fnH0QQe4

[dorooleg]

• A stripped-down version of scheduling algorithms

[lebedev.ri]

I think this is missing an actual differential's description.

[dorooleg]

• fuzzing scheduler with use watch dog
• Unused stats removed

[lebedev.ri]

In D65383#1605212, @lebedev.ri wrote:

I think this is missing an actual differential's description.

Still so.
Where's the actual RFC?

[dorooleg]

Attached a discussion link in the description. What kind of RFC are we talking about?

[lebedev.ri]

In D65383#1629867, @dorooleg wrote:

What kind of RFC are we talking about?

I personally expected to see [RFC] TSan: introduce fuzzing scheduler on/CC'd to llvm-dev.

Attached a discussion link in the description.

Thanks, that's better.

lib/tsan/CMakeLists.txt

set(TSAN_SOURCES
   rtl/tsan_rtl_proc.cpp
   rtl/tsan_rtl_report.cpp
   rtl/tsan_rtl_thread.cpp
   rtl/tsan_stack_trace.cpp
   rtl/tsan_stat.cpp
   rtl/tsan_suppressions.cpp
   rtl/tsan_symbolize.cpp
   rtl/tsan_sync.cpp
+  rtl/fuzzing_scheduler/fuzzing_scheduler.cpp
   )
 
 set(TSAN_CXX_SOURCES
   rtl/tsan_new_delete.cpp
   )
 
 if(APPLE)
   list(APPEND TSAN_SOURCES
set(TSAN_HEADERS
   rtl/tsan_report.h
   rtl/tsan_rtl.h
   rtl/tsan_stack_trace.h
   rtl/tsan_stat.h
   rtl/tsan_suppressions.h
   rtl/tsan_symbolize.h
   rtl/tsan_sync.h
   rtl/tsan_trace.h
-  rtl/tsan_update_shadow_word_inl.h)
+  rtl/tsan_update_shadow_word_inl.h
+  rtl/fuzzing_scheduler/fuzzing_scheduler.h)
 
 set(TSAN_RUNTIME_LIBRARIES)
 add_compiler_rt_component(tsan)
 
 if(APPLE)
   add_asm_sources(TSAN_ASM_SOURCES rtl/tsan_rtl_amd64.S rtl/tsan_rtl_aarch64.S)
 
   set(TSAN_LINK_LIBS ${SANITIZER_COMMON_LINK_LIBS})

lib/tsan/rtl/fuzzing_scheduler/fuzzing_scheduler.h

+#pragma once
+
+namespace __tsan {
+
+struct IFuzzingScheduler
+{
+    virtual void SynchronizationPoint() = 0;
+};
+
+IFuzzingScheduler& GetFuzzingScheduler();
+
+}  // namespace __tsan

lib/tsan/rtl/fuzzing_scheduler/fuzzing_scheduler.cpp

+#include "fuzzing_scheduler.h"
+#include <rtl/tsan_rtl.h>
+#include <sanitizer_common/sanitizer_allocator_internal.h>
+#include <sanitizer_common/sanitizer_placement_new.h>
+#include <interception/interception.h>
+#include <cstring>
+#include <cstdlib>
+#include <unistd.h>
+
+namespace __interception {
+  extern int (*real_pthread_create)(void*, void*, void *(*)(void*), void*);
+  extern int (*real_pthread_detach)(void*);
+}
+
+namespace __tsan {
+
+namespace {
+
+struct NullFuzzingScheduler : IFuzzingScheduler {
+  void SynchronizationPoint() override {
+  }
+};
+
+thread_local u64 tid = 0;
+u64 max_tid = 0;
+
+struct RandomFuzzingScheduler : IFuzzingScheduler {
+  RandomFuzzingScheduler() {
+    srand(NanoTime());
+    pthread_t t;
+    REAL(pthread_create)(&t, NULL, reinterpret_cast<void*(*)(void*)>(&RandomFuzzingScheduler::WatchDog), this);
+    REAL(pthread_detach)(&t);
+  }
+
+
+private:
+  enum class ThreadState {
+    UNKNOWN,
+    RUNNING,
+    WAIT,
+    OUT_TIME
+  };
+
+  struct ThreadContext {
+    ThreadState state = ThreadState::UNKNOWN;
+    u64 start_time = 0;
+  };
+
+  ThreadContext contexts[65536] = {};
+  Stats stats;
+
+  u64 GetTid() {
+    if (tid == 0) {
+      tid = __atomic_add_fetch(&max_tid, 1, __ATOMIC_RELAXED);
+    }
+    if (tid > 65535) {
+      Printf("FATAL: ThreadSanitizer The maximum number of threads created during the program should not exceed 65535");
+      Die();
+    }
+    return tid;
+  }
+
+  void SynchronizationPoint() override {
+    auto tid = GetTid();
+    auto old_state = __atomic_load_n(&contexts[tid].state, __ATOMIC_SEQ_CST);
+    __atomic_store_n(&contexts[tid].state, ThreadState::WAIT, __ATOMIC_SEQ_CST);
+    if (old_state == ThreadState::RUNNING) {
+      auto next_tid = GetNextTid();
+      __atomic_store_n(&contexts[next_tid].start_time, NanoTime(), __ATOMIC_SEQ_CST);
+      __atomic_store_n(&contexts[next_tid].state, ThreadState::RUNNING, __ATOMIC_SEQ_CST);
+    }
+    //PrintStates();
+    while (__atomic_load_n(&contexts[tid].state, __ATOMIC_SEQ_CST) == ThreadState::WAIT) {
+      internal_sched_yield();
+    }
+  }
+
+  u64 GetNextTid() {
+      const u64 local_max_tid = __atomic_load_n(&max_tid, __ATOMIC_SEQ_CST);
+      const u64 next_tid = rand() % local_max_tid + 1;
+      for (u64 i = 0; i < local_max_tid; i++) {
+        if (__atomic_load_n(&contexts[(next_tid + i) % max_tid + 1].state, __ATOMIC_SEQ_CST) == ThreadState::WAIT) {
+          return (next_tid + i) % max_tid + 1;
+        }
+      }
+      return next_tid;
+  }
+
+  void* WatchDog() {
+    while (true) {
+      usleep(200 * 1000);
+      u64 local_max_tid = __atomic_load_n(&max_tid, __ATOMIC_SEQ_CST);
+      for (u64 i = 1; i <= local_max_tid; i++) {
+        if (__atomic_load_n(&contexts[i].state, __ATOMIC_SEQ_CST) == ThreadState::RUNNING && __atomic_load_n(&contexts[i].start_time, __ATOMIC_SEQ_CST) + 200 * 1000 * 1000ULL <= NanoTime()) {
+          __atomic_store_n(&contexts[i].state, ThreadState::OUT_TIME, __ATOMIC_SEQ_CST);
+        }
+      }
+      bool exists_running = false;
+      for (u64 i = 1; i <= local_max_tid; i++) {
+        if (__atomic_load_n(&contexts[i].state, __ATOMIC_SEQ_CST) == ThreadState::RUNNING) {
+          exists_running = true;
+        }
+      }
+      if (!exists_running) {
+        auto next_tid = GetNextTid();
+        __atomic_store_n(&contexts[next_tid].start_time, NanoTime(), __ATOMIC_SEQ_CST);
+        __atomic_store_n(&contexts[next_tid].state, ThreadState::RUNNING, __ATOMIC_SEQ_CST);
+      }
+    }
+    return nullptr;
+  }
+
+};
+
+IFuzzingScheduler& FuzzingSchedulerDispatcher() {
+  if (!strcmp(flags()->fuzzing_scheduler, "")) {
+    auto* scheduler = static_cast<NullFuzzingScheduler *>(InternalCalloc(1, sizeof(NullFuzzingScheduler)));
+    new (scheduler) NullFuzzingScheduler;
+    return *scheduler;
+  } else if (!strcmp(flags()->fuzzing_scheduler, "random")) {
+    auto* scheduler = static_cast<RandomFuzzingScheduler *>(InternalCalloc(1, sizeof(RandomFuzzingScheduler)));
+    new (scheduler) RandomFuzzingScheduler;
+    Printf("WARNING! ThreadSanitizer lunched under the management of a random fuzzing scheduler new\n");
+    return *scheduler;
+  } else {
+    Printf("FATAL: ThreadSanitizer invalid fuzzing scheduler. Please check TSAN_OPTIONS!\n");
+    Die();
+  }
+}
+
+}
+
+IFuzzingScheduler& GetFuzzingScheduler() {
+  static IFuzzingScheduler& scheduler = FuzzingSchedulerDispatcher();
+  return scheduler;
+}
+
+}  // namespace __tsan

lib/tsan/rtl/tsan_flags.inc

 TSAN_FLAG(bool, die_after_fork, true,
           "Die after multi-threaded fork if the child creates new threads.")
 TSAN_FLAG(const char *, suppressions, "", "Suppressions file name.")
 TSAN_FLAG(bool, ignore_noninstrumented_modules, SANITIZER_MAC ? true : false,
           "Interceptors should only detect races when called from instrumented "
           "modules.")
 TSAN_FLAG(bool, shared_ptr_interceptor, true,
           "Track atomic reference counting in libc++ shared_ptr and weak_ptr.")
+TSAN_FLAG(const char *, fuzzing_scheduler, "",
+          "Choosing fuzzing scheduler")

lib/tsan/rtl/tsan_interceptors.cpp

 #include "interception/interception.h"
 #include "tsan_interceptors.h"
 #include "tsan_interface.h"
 #include "tsan_platform.h"
 #include "tsan_suppressions.h"
 #include "tsan_rtl.h"
 #include "tsan_mman.h"
 #include "tsan_fd.h"
+#include "fuzzing_scheduler/fuzzing_scheduler.h"
 
 
 using namespace __tsan;  // NOLINT
 
 #if SANITIZER_FREEBSD || SANITIZER_MAC
 #define stdout __stdoutp
 #define stderr __stderrp
 #endif
#if !SANITIZER_MAC && !SANITIZER_NETBSD && !SANITIZER_FREEBSD
     ThreadIgnoreEnd(thr, 0);
 #endif
     while ((tid = atomic_load(&p->tid, memory_order_acquire)) == 0)
       internal_sched_yield();
     Processor *proc = ProcCreate();
     ProcWire(proc, thr);
     ThreadStart(thr, tid, GetTid(), ThreadType::Regular);
     atomic_store(&p->tid, 0, memory_order_release);
+    GetFuzzingScheduler().SynchronizationPoint();
   }
   void *res = callback(param);
   // Prevent the callback from being tail called,
   // it mixes up stack traces.
   volatile int foo = 42;
   foo++;
   return res;
 }
if (ctx->after_multithreaded_fork) {
     }
   }
   __sanitizer_pthread_attr_t myattr;
   if (attr == 0) {
     pthread_attr_init(&myattr);
     attr = &myattr;
   }
   int detached = 0;
+  GetFuzzingScheduler().SynchronizationPoint();
   REAL(pthread_attr_getdetachstate)(attr, &detached);
   AdjustStackSize(attr);
 
   ThreadParam p;
   p.callback = callback;
   p.param = param;
   atomic_store(&p.tid, 0, memory_order_relaxed);
   int res = -1;
   {
     // Otherwise we see false positives in pthread stack manipulation.
     ScopedIgnoreInterceptors ignore;
     ThreadIgnoreBegin(thr, pc);
+    GetFuzzingScheduler().SynchronizationPoint();
     res = REAL(pthread_create)(th, attr, __tsan_thread_start_func, &p);
     ThreadIgnoreEnd(thr, pc);
   }
   if (res == 0) {
     int tid = ThreadCreate(thr, pc, *(uptr*)th, IsStateDetached(detached));
     CHECK_NE(tid, 0);
     // Synchronization on p.tid serves two purposes:
     // 1. ThreadCreate must finish before the new thread starts.
     //    Otherwise the new thread can call pthread_detach, but the pthread_t
     //    identifier is not yet registered in ThreadRegistry by ThreadCreate.
     // 2. ThreadStart must finish before this thread continues.
     //    Otherwise, this thread can call pthread_detach and reset thr->sync
     //    before the new thread got a chance to acquire from it in ThreadStart.
     atomic_store(&p.tid, tid, memory_order_release);
     while (atomic_load(&p.tid, memory_order_acquire) != 0)
       internal_sched_yield();
   }
   if (attr == &myattr)
     pthread_attr_destroy(&myattr);
+  GetFuzzingScheduler().SynchronizationPoint();
   return res;
 }
 
 TSAN_INTERCEPTOR(int, pthread_join, void *th, void **ret) {
   SCOPED_INTERCEPTOR_RAW(pthread_join, th, ret);
   int tid = ThreadTid(thr, pc, (uptr)th);
   ThreadIgnoreBegin(thr, pc);
+  GetFuzzingScheduler().SynchronizationPoint();
   int res = BLOCK_REAL(pthread_join)(th, ret);
   ThreadIgnoreEnd(thr, pc);
   if (res == 0) {
     ThreadJoin(thr, pc, tid);
   }
   return res;
 }
 
 DEFINE_REAL_PTHREAD_FUNCTIONS
 
 TSAN_INTERCEPTOR(int, pthread_detach, void *th) {
   SCOPED_TSAN_INTERCEPTOR(pthread_detach, th);
   int tid = ThreadTid(thr, pc, (uptr)th);
+  GetFuzzingScheduler().SynchronizationPoint();
   int res = REAL(pthread_detach)(th);
   if (res == 0) {
     ThreadDetach(thr, pc, tid);
   }
   return res;
 }
 
 TSAN_INTERCEPTOR(void, pthread_exit, void *retval) {
   {
     SCOPED_INTERCEPTOR_RAW(pthread_exit, retval);
 #if !SANITIZER_MAC && !SANITIZER_ANDROID
     CHECK_EQ(thr, &cur_thread_placeholder);
 #endif
   }
+  GetFuzzingScheduler().SynchronizationPoint();
   REAL(pthread_exit)(retval);
 }
 
 #if SANITIZER_LINUX
 TSAN_INTERCEPTOR(int, pthread_tryjoin_np, void *th, void **ret) {
   SCOPED_TSAN_INTERCEPTOR(pthread_tryjoin_np, th, ret);
   int tid = ThreadTid(thr, pc, (uptr)th);
   ThreadIgnoreBegin(thr, pc);
+  GetFuzzingScheduler().SynchronizationPoint();
   int res = REAL(pthread_tryjoin_np)(th, ret);
   ThreadIgnoreEnd(thr, pc);
   if (res == 0)
     ThreadJoin(thr, pc, tid);
   else
     ThreadNotJoined(thr, pc, tid, (uptr)th);
   return res;
 }
 
 TSAN_INTERCEPTOR(int, pthread_timedjoin_np, void *th, void **ret,
                  const struct timespec *abstime) {
   SCOPED_TSAN_INTERCEPTOR(pthread_timedjoin_np, th, ret, abstime);
   int tid = ThreadTid(thr, pc, (uptr)th);
   ThreadIgnoreBegin(thr, pc);
+  GetFuzzingScheduler().SynchronizationPoint();
   int res = BLOCK_REAL(pthread_timedjoin_np)(th, ret, abstime);
   ThreadIgnoreEnd(thr, pc);
   if (res == 0)
     ThreadJoin(thr, pc, tid);
   else
     ThreadNotJoined(thr, pc, tid, (uptr)th);
   return res;
 }
static void cond_mutex_unlock(CondMutexUnlockCtx *arg) {
   arg->thr->ignore_interceptors--;
   arg->si->~ScopedInterceptor();
 }
 
 INTERCEPTOR(int, pthread_cond_init, void *c, void *a) {
   void *cond = init_cond(c, true);
   SCOPED_TSAN_INTERCEPTOR(pthread_cond_init, cond, a);
   MemoryAccessRange(thr, pc, (uptr)c, sizeof(uptr), true);
+  GetFuzzingScheduler().SynchronizationPoint();
   return REAL(pthread_cond_init)(cond, a);
 }
 
 static int cond_wait(ThreadState *thr, uptr pc, ScopedInterceptor *si,
                      int (*fn)(void *c, void *m, void *abstime), void *c,
                      void *m, void *t) {
   MemoryAccessRange(thr, pc, (uptr)c, sizeof(uptr), false);
   MutexUnlock(thr, pc, (uptr)m);
static int cond_wait(ThreadState *thr, uptr pc, ScopedInterceptor *si,
   if (res == errno_EOWNERDEAD) MutexRepair(thr, pc, (uptr)m);
   MutexPostLock(thr, pc, (uptr)m, MutexFlagDoPreLockOnPostLock);
   return res;
 }
 
 INTERCEPTOR(int, pthread_cond_wait, void *c, void *m) {
   void *cond = init_cond(c);
   SCOPED_TSAN_INTERCEPTOR(pthread_cond_wait, cond, m);
+  GetFuzzingScheduler().SynchronizationPoint();
   return cond_wait(thr, pc, &si, (int (*)(void *c, void *m, void *abstime))REAL(
                                      pthread_cond_wait),
                    cond, m, 0);
 }
 
 INTERCEPTOR(int, pthread_cond_timedwait, void *c, void *m, void *abstime) {
   void *cond = init_cond(c);
   SCOPED_TSAN_INTERCEPTOR(pthread_cond_timedwait, cond, m, abstime);
+  GetFuzzingScheduler().SynchronizationPoint();
   return cond_wait(thr, pc, &si, REAL(pthread_cond_timedwait), cond, m,
                    abstime);
 }
 
 #if SANITIZER_MAC
 INTERCEPTOR(int, pthread_cond_timedwait_relative_np, void *c, void *m,
             void *reltime) {
   void *cond = init_cond(c);
   SCOPED_TSAN_INTERCEPTOR(pthread_cond_timedwait_relative_np, cond, m, reltime);
+  GetFuzzingScheduler().SynchronizationPoint();
   return cond_wait(thr, pc, &si, REAL(pthread_cond_timedwait_relative_np), cond,
                    m, reltime);
 }
 #endif
 
 INTERCEPTOR(int, pthread_cond_signal, void *c) {
   void *cond = init_cond(c);
   SCOPED_TSAN_INTERCEPTOR(pthread_cond_signal, cond);
   MemoryAccessRange(thr, pc, (uptr)c, sizeof(uptr), false);
+  GetFuzzingScheduler().SynchronizationPoint();
   return REAL(pthread_cond_signal)(cond);
 }
 
 INTERCEPTOR(int, pthread_cond_broadcast, void *c) {
   void *cond = init_cond(c);
   SCOPED_TSAN_INTERCEPTOR(pthread_cond_broadcast, cond);
   MemoryAccessRange(thr, pc, (uptr)c, sizeof(uptr), false);
+  GetFuzzingScheduler().SynchronizationPoint();
   return REAL(pthread_cond_broadcast)(cond);
 }
 
 INTERCEPTOR(int, pthread_cond_destroy, void *c) {
   void *cond = init_cond(c);
   SCOPED_TSAN_INTERCEPTOR(pthread_cond_destroy, cond);
   MemoryAccessRange(thr, pc, (uptr)c, sizeof(uptr), true);
+  GetFuzzingScheduler().SynchronizationPoint();
   int res = REAL(pthread_cond_destroy)(cond);
   if (common_flags()->legacy_pthread_cond) {
     // Free our aux cond and zero the pointer to not leave dangling pointers.
     WRAP(free)(cond);
     atomic_store((atomic_uintptr_t*)c, 0, memory_order_relaxed);
   }
   return res;
 }
 
 TSAN_INTERCEPTOR(int, pthread_mutex_init, void *m, void *a) {
   SCOPED_TSAN_INTERCEPTOR(pthread_mutex_init, m, a);
   int res = REAL(pthread_mutex_init)(m, a);
   if (res == 0) {
     u32 flagz = 0;
     if (a) {
       int type = 0;
+      GetFuzzingScheduler().SynchronizationPoint();
       if (REAL(pthread_mutexattr_gettype)(a, &type) == 0)
         if (type == PTHREAD_MUTEX_RECURSIVE ||
             type == PTHREAD_MUTEX_RECURSIVE_NP)
           flagz |= MutexFlagWriteReentrant;
     }
     MutexCreate(thr, pc, (uptr)m, flagz);
   }
   return res;
 }
 
 TSAN_INTERCEPTOR(int, pthread_mutex_destroy, void *m) {
   SCOPED_TSAN_INTERCEPTOR(pthread_mutex_destroy, m);
+  GetFuzzingScheduler().SynchronizationPoint();
   int res = REAL(pthread_mutex_destroy)(m);
   if (res == 0 || res == errno_EBUSY) {
     MutexDestroy(thr, pc, (uptr)m);
   }
   return res;
 }
 
 TSAN_INTERCEPTOR(int, pthread_mutex_trylock, void *m) {
   SCOPED_TSAN_INTERCEPTOR(pthread_mutex_trylock, m);
+  GetFuzzingScheduler().SynchronizationPoint();
   int res = REAL(pthread_mutex_trylock)(m);
   if (res == errno_EOWNERDEAD)
     MutexRepair(thr, pc, (uptr)m);
   if (res == 0 || res == errno_EOWNERDEAD)
     MutexPostLock(thr, pc, (uptr)m, MutexFlagTryLock);
   return res;
 }
 
 #if !SANITIZER_MAC
 TSAN_INTERCEPTOR(int, pthread_mutex_timedlock, void *m, void *abstime) {
   SCOPED_TSAN_INTERCEPTOR(pthread_mutex_timedlock, m, abstime);
+  GetFuzzingScheduler().SynchronizationPoint();
   int res = REAL(pthread_mutex_timedlock)(m, abstime);
   if (res == 0) {
     MutexPostLock(thr, pc, (uptr)m, MutexFlagTryLock);
   }
   return res;
 }
 #endif
 
 #if !SANITIZER_MAC
 TSAN_INTERCEPTOR(int, pthread_spin_init, void *m, int pshared) {
   SCOPED_TSAN_INTERCEPTOR(pthread_spin_init, m, pshared);
+  GetFuzzingScheduler().SynchronizationPoint();
   int res = REAL(pthread_spin_init)(m, pshared);
   if (res == 0) {
     MutexCreate(thr, pc, (uptr)m);
   }
   return res;
 }
 
 TSAN_INTERCEPTOR(int, pthread_spin_destroy, void *m) {
   SCOPED_TSAN_INTERCEPTOR(pthread_spin_destroy, m);
+  GetFuzzingScheduler().SynchronizationPoint();
   int res = REAL(pthread_spin_destroy)(m);
   if (res == 0) {
     MutexDestroy(thr, pc, (uptr)m);
   }
   return res;
 }
 
 TSAN_INTERCEPTOR(int, pthread_spin_lock, void *m) {
   SCOPED_TSAN_INTERCEPTOR(pthread_spin_lock, m);
   MutexPreLock(thr, pc, (uptr)m);
+  GetFuzzingScheduler().SynchronizationPoint();
   int res = REAL(pthread_spin_lock)(m);
   if (res == 0) {
     MutexPostLock(thr, pc, (uptr)m);
   }
   return res;
 }
 
 TSAN_INTERCEPTOR(int, pthread_spin_trylock, void *m) {
   SCOPED_TSAN_INTERCEPTOR(pthread_spin_trylock, m);
+  GetFuzzingScheduler().SynchronizationPoint();
   int res = REAL(pthread_spin_trylock)(m);
   if (res == 0) {
     MutexPostLock(thr, pc, (uptr)m, MutexFlagTryLock);
   }
   return res;
 }
 
 TSAN_INTERCEPTOR(int, pthread_spin_unlock, void *m) {
   SCOPED_TSAN_INTERCEPTOR(pthread_spin_unlock, m);
+  GetFuzzingScheduler().SynchronizationPoint();
   MutexUnlock(thr, pc, (uptr)m);
   int res = REAL(pthread_spin_unlock)(m);
   return res;
 }
 #endif
 
 TSAN_INTERCEPTOR(int, pthread_rwlock_init, void *m, void *a) {
   SCOPED_TSAN_INTERCEPTOR(pthread_rwlock_init, m, a);
+  GetFuzzingScheduler().SynchronizationPoint();
   int res = REAL(pthread_rwlock_init)(m, a);
   if (res == 0) {
     MutexCreate(thr, pc, (uptr)m);
   }
   return res;
 }
 
 TSAN_INTERCEPTOR(int, pthread_rwlock_destroy, void *m) {
   SCOPED_TSAN_INTERCEPTOR(pthread_rwlock_destroy, m);
+  GetFuzzingScheduler().SynchronizationPoint();
   int res = REAL(pthread_rwlock_destroy)(m);
   if (res == 0) {
     MutexDestroy(thr, pc, (uptr)m);
   }
   return res;
 }
 
 TSAN_INTERCEPTOR(int, pthread_rwlock_rdlock, void *m) {
   SCOPED_TSAN_INTERCEPTOR(pthread_rwlock_rdlock, m);
   MutexPreReadLock(thr, pc, (uptr)m);
+  GetFuzzingScheduler().SynchronizationPoint();
   int res = REAL(pthread_rwlock_rdlock)(m);
   if (res == 0) {
     MutexPostReadLock(thr, pc, (uptr)m);
   }
   return res;
 }
 
 TSAN_INTERCEPTOR(int, pthread_rwlock_tryrdlock, void *m) {
   SCOPED_TSAN_INTERCEPTOR(pthread_rwlock_tryrdlock, m);
+  GetFuzzingScheduler().SynchronizationPoint();
   int res = REAL(pthread_rwlock_tryrdlock)(m);
   if (res == 0) {
     MutexPostReadLock(thr, pc, (uptr)m, MutexFlagTryLock);
   }
   return res;
 }
 
 #if !SANITIZER_MAC
 TSAN_INTERCEPTOR(int, pthread_rwlock_timedrdlock, void *m, void *abstime) {
   SCOPED_TSAN_INTERCEPTOR(pthread_rwlock_timedrdlock, m, abstime);
+  GetFuzzingScheduler().SynchronizationPoint();
   int res = REAL(pthread_rwlock_timedrdlock)(m, abstime);
   if (res == 0) {
     MutexPostReadLock(thr, pc, (uptr)m);
   }
   return res;
 }
 #endif
 
 TSAN_INTERCEPTOR(int, pthread_rwlock_wrlock, void *m) {
   SCOPED_TSAN_INTERCEPTOR(pthread_rwlock_wrlock, m);
   MutexPreLock(thr, pc, (uptr)m);
+  GetFuzzingScheduler().SynchronizationPoint();
   int res = REAL(pthread_rwlock_wrlock)(m);
   if (res == 0) {
     MutexPostLock(thr, pc, (uptr)m);
   }
   return res;
 }
 
 TSAN_INTERCEPTOR(int, pthread_rwlock_trywrlock, void *m) {
   SCOPED_TSAN_INTERCEPTOR(pthread_rwlock_trywrlock, m);
+  GetFuzzingScheduler().SynchronizationPoint();
   int res = REAL(pthread_rwlock_trywrlock)(m);
   if (res == 0) {
     MutexPostLock(thr, pc, (uptr)m, MutexFlagTryLock);
   }
   return res;
 }
 
 #if !SANITIZER_MAC
 TSAN_INTERCEPTOR(int, pthread_rwlock_timedwrlock, void *m, void *abstime) {
   SCOPED_TSAN_INTERCEPTOR(pthread_rwlock_timedwrlock, m, abstime);
+  GetFuzzingScheduler().SynchronizationPoint();
   int res = REAL(pthread_rwlock_timedwrlock)(m, abstime);
   if (res == 0) {
     MutexPostLock(thr, pc, (uptr)m, MutexFlagTryLock);
   }
   return res;
 }
 #endif
 
 TSAN_INTERCEPTOR(int, pthread_rwlock_unlock, void *m) {
   SCOPED_TSAN_INTERCEPTOR(pthread_rwlock_unlock, m);
   MutexReadOrWriteUnlock(thr, pc, (uptr)m);
+  GetFuzzingScheduler().SynchronizationPoint();
   int res = REAL(pthread_rwlock_unlock)(m);
   return res;
 }
 
 #if !SANITIZER_MAC
 TSAN_INTERCEPTOR(int, pthread_barrier_init, void *b, void *a, unsigned count) {
   SCOPED_TSAN_INTERCEPTOR(pthread_barrier_init, b, a, count);
   MemoryWrite(thr, pc, (uptr)b, kSizeLog1);
+  GetFuzzingScheduler().SynchronizationPoint();
   int res = REAL(pthread_barrier_init)(b, a, count);
   return res;
 }
 
 TSAN_INTERCEPTOR(int, pthread_barrier_destroy, void *b) {
   SCOPED_TSAN_INTERCEPTOR(pthread_barrier_destroy, b);
   MemoryWrite(thr, pc, (uptr)b, kSizeLog1);
+  GetFuzzingScheduler().SynchronizationPoint();
   int res = REAL(pthread_barrier_destroy)(b);
   return res;
 }
 
 TSAN_INTERCEPTOR(int, pthread_barrier_wait, void *b) {
   SCOPED_TSAN_INTERCEPTOR(pthread_barrier_wait, b);
   Release(thr, pc, (uptr)b);
   MemoryRead(thr, pc, (uptr)b, kSizeLog1);

 TSAN_INTERCEPTOR(int, sigsetmask, int mask) {
   SCOPED_TSAN_INTERCEPTOR(sigsetmask, mask);
   return REAL(sigsetmask)(mask);
 }
 
 TSAN_INTERCEPTOR(int, pthread_sigmask, int how, const __sanitizer_sigset_t *set,
     __sanitizer_sigset_t *oldset) {
   SCOPED_TSAN_INTERCEPTOR(pthread_sigmask, how, set, oldset);
+  GetFuzzingScheduler().SynchronizationPoint();
   return REAL(pthread_sigmask)(how, set, oldset);
 }
 
 namespace __tsan {
 
 static void CallUserSignalHandler(ThreadState *thr, bool sync, bool acquire,
                                   bool sigact, int sig,
                                   __sanitizer_siginfo *info, void *uctx) {
void ProcessPendingSignals(ThreadState *thr) {
   for (int sig = 0; sig < kSigCount; sig++) {
     SignalDesc *signal = &sctx->pending_signals[sig];
     if (signal->armed) {
       signal->armed = false;
       CallUserSignalHandler(thr, false, true, signal->sigaction, sig,
           &signal->siginfo, &signal->ctx);
     }
   }
+  GetFuzzingScheduler().SynchronizationPoint();
   res = REAL(pthread_sigmask)(SIG_SETMASK, &sctx->oldset, 0);
   CHECK_EQ(res, 0);
   atomic_fetch_add(&thr->in_signal_handler, -1, memory_order_relaxed);
 }
 
 }  // namespace __tsan
 
 static bool is_sync_signal(ThreadSignalContext *sctx, int sig) {

 TSAN_INTERCEPTOR(int, pthread_kill, void *tid, int sig) {
   SCOPED_TSAN_INTERCEPTOR(pthread_kill, tid, sig);
   ThreadSignalContext *sctx = SigCtx(thr);
   CHECK_NE(sctx, 0);
   int prev = sctx->int_signal_send;
   if (tid == pthread_self()) {
     sctx->int_signal_send = sig;
   }
+  GetFuzzingScheduler().SynchronizationPoint();
   int res = REAL(pthread_kill)(tid, sig);
   if (tid == pthread_self()) {
     CHECK_EQ(sctx->int_signal_send, sig);
     sctx->int_signal_send = prev;
   }
   return res;
 }
 

lib/tsan/rtl/tsan_interface_atomic.cpp

 // http://www.hpl.hp.com/personal/Hans_Boehm/c++mm/
 
 #include "sanitizer_common/sanitizer_placement_new.h"
 #include "sanitizer_common/sanitizer_stacktrace.h"
 #include "sanitizer_common/sanitizer_mutex.h"
 #include "tsan_flags.h"
 #include "tsan_interface.h"
 #include "tsan_rtl.h"
+#include "fuzzing_scheduler/fuzzing_scheduler.h"
 
 using namespace __tsan;  // NOLINT
 
 #if !SANITIZER_GO && __TSAN_HAS_INT128
 // Protects emulation of 128-bit atomic operations.
 static StaticSpinMutex mutex128;
 #endif
 

 
 static bool IsAcqRelOrder(morder mo) {
   return mo == mo_acq_rel || mo == mo_seq_cst;
 }
 
 template<typename T> T func_xchg(volatile T *v, T op) {
   T res = __sync_lock_test_and_set(v, op);
   // __sync_lock_test_and_set does not contain full barrier.
+  GetFuzzingScheduler().SynchronizationPoint();
   __sync_synchronize();
   return res;
 }
 
 template<typename T> T func_add(volatile T *v, T op) {
+  GetFuzzingScheduler().SynchronizationPoint();
   return __sync_fetch_and_add(v, op);
 }
 
 template<typename T> T func_sub(volatile T *v, T op) {
   return __sync_fetch_and_sub(v, op);
 }
 
 template<typename T> T func_and(volatile T *v, T op) {
StatInc(thr, mo == mo_relaxed ? StatAtomicRelaxed
              : mo == mo_release ? StatAtomicRelease
              : mo == mo_acq_rel ? StatAtomicAcq_Rel
              :                    StatAtomicSeq_Cst);
 }
 
 extern "C" {
 SANITIZER_INTERFACE_ATTRIBUTE
 a8 __tsan_atomic8_load(const volatile a8 *a, morder mo) {
+  GetFuzzingScheduler().SynchronizationPoint();
   SCOPED_ATOMIC(Load, a, mo);
 }
 
 SANITIZER_INTERFACE_ATTRIBUTE
 a16 __tsan_atomic16_load(const volatile a16 *a, morder mo) {
+  GetFuzzingScheduler().SynchronizationPoint();
   SCOPED_ATOMIC(Load, a, mo);
 }
 
 SANITIZER_INTERFACE_ATTRIBUTE
 a32 __tsan_atomic32_load(const volatile a32 *a, morder mo) {
+  GetFuzzingScheduler().SynchronizationPoint();
   SCOPED_ATOMIC(Load, a, mo);
 }
 
 SANITIZER_INTERFACE_ATTRIBUTE
 a64 __tsan_atomic64_load(const volatile a64 *a, morder mo) {
+  GetFuzzingScheduler().SynchronizationPoint();
   SCOPED_ATOMIC(Load, a, mo);
 }
 
 #if __TSAN_HAS_INT128
 SANITIZER_INTERFACE_ATTRIBUTE
 a128 __tsan_atomic128_load(const volatile a128 *a, morder mo) {
+  GetFuzzingScheduler().SynchronizationPoint();
   SCOPED_ATOMIC(Load, a, mo);
 }
 #endif
 
 SANITIZER_INTERFACE_ATTRIBUTE
 void __tsan_atomic8_store(volatile a8 *a, a8 v, morder mo) {
+  GetFuzzingScheduler().SynchronizationPoint();
   SCOPED_ATOMIC(Store, a, v, mo);
 }
 
 SANITIZER_INTERFACE_ATTRIBUTE
 void __tsan_atomic16_store(volatile a16 *a, a16 v, morder mo) {
+  GetFuzzingScheduler().SynchronizationPoint();
   SCOPED_ATOMIC(Store, a, v, mo);
 }
 
 SANITIZER_INTERFACE_ATTRIBUTE
 void __tsan_atomic32_store(volatile a32 *a, a32 v, morder mo) {
+  GetFuzzingScheduler().SynchronizationPoint();
   SCOPED_ATOMIC(Store, a, v, mo);
 }
 
 SANITIZER_INTERFACE_ATTRIBUTE
 void __tsan_atomic64_store(volatile a64 *a, a64 v, morder mo) {
+  GetFuzzingScheduler().SynchronizationPoint();
   SCOPED_ATOMIC(Store, a, v, mo);
 }
 
 #if __TSAN_HAS_INT128
 SANITIZER_INTERFACE_ATTRIBUTE
 void __tsan_atomic128_store(volatile a128 *a, a128 v, morder mo) {
+  GetFuzzingScheduler().SynchronizationPoint();
   SCOPED_ATOMIC(Store, a, v, mo);
 }
 #endif
 
 SANITIZER_INTERFACE_ATTRIBUTE
 a8 __tsan_atomic8_exchange(volatile a8 *a, a8 v, morder mo) {
+  GetFuzzingScheduler().SynchronizationPoint();
   SCOPED_ATOMIC(Exchange, a, v, mo);
 }
 
 SANITIZER_INTERFACE_ATTRIBUTE
 a16 __tsan_atomic16_exchange(volatile a16 *a, a16 v, morder mo) {
+  GetFuzzingScheduler().SynchronizationPoint();
   SCOPED_ATOMIC(Exchange, a, v, mo);
 }
 
 SANITIZER_INTERFACE_ATTRIBUTE
 a32 __tsan_atomic32_exchange(volatile a32 *a, a32 v, morder mo) {
+  GetFuzzingScheduler().SynchronizationPoint();
   SCOPED_ATOMIC(Exchange, a, v, mo);
 }
 
 SANITIZER_INTERFACE_ATTRIBUTE
 a64 __tsan_atomic64_exchange(volatile a64 *a, a64 v, morder mo) {
+  GetFuzzingScheduler().SynchronizationPoint();
   SCOPED_ATOMIC(Exchange, a, v, mo);
 }
 
 #if __TSAN_HAS_INT128
 SANITIZER_INTERFACE_ATTRIBUTE
 a128 __tsan_atomic128_exchange(volatile a128 *a, a128 v, morder mo) {
+  GetFuzzingScheduler().SynchronizationPoint();
   SCOPED_ATOMIC(Exchange, a, v, mo);
 }
 #endif
 
 SANITIZER_INTERFACE_ATTRIBUTE
 a8 __tsan_atomic8_fetch_add(volatile a8 *a, a8 v, morder mo) {
+  GetFuzzingScheduler().SynchronizationPoint();
   SCOPED_ATOMIC(FetchAdd, a, v, mo);
 }
 
 SANITIZER_INTERFACE_ATTRIBUTE
 a16 __tsan_atomic16_fetch_add(volatile a16 *a, a16 v, morder mo) {
+  GetFuzzingScheduler().SynchronizationPoint();
   SCOPED_ATOMIC(FetchAdd, a, v, mo);
 }
 
 SANITIZER_INTERFACE_ATTRIBUTE
 a32 __tsan_atomic32_fetch_add(volatile a32 *a, a32 v, morder mo) {
+  GetFuzzingScheduler().SynchronizationPoint();
   SCOPED_ATOMIC(FetchAdd, a, v, mo);
 }
 
 SANITIZER_INTERFACE_ATTRIBUTE
 a64 __tsan_atomic64_fetch_add(volatile a64 *a, a64 v, morder mo) {
+  GetFuzzingScheduler().SynchronizationPoint();
   SCOPED_ATOMIC(FetchAdd, a, v, mo);
 }
 
 #if __TSAN_HAS_INT128
 SANITIZER_INTERFACE_ATTRIBUTE
 a128 __tsan_atomic128_fetch_add(volatile a128 *a, a128 v, morder mo) {
+  GetFuzzingScheduler().SynchronizationPoint();
   SCOPED_ATOMIC(FetchAdd, a, v, mo);
 }
 #endif
 
 SANITIZER_INTERFACE_ATTRIBUTE
 a8 __tsan_atomic8_fetch_sub(volatile a8 *a, a8 v, morder mo) {
+  GetFuzzingScheduler().SynchronizationPoint();
   SCOPED_ATOMIC(FetchSub, a, v, mo);
 }
 
 SANITIZER_INTERFACE_ATTRIBUTE
 a16 __tsan_atomic16_fetch_sub(volatile a16 *a, a16 v, morder mo) {
+  GetFuzzingScheduler().SynchronizationPoint();
   SCOPED_ATOMIC(FetchSub, a, v, mo);
 }
 
 SANITIZER_INTERFACE_ATTRIBUTE
 a32 __tsan_atomic32_fetch_sub(volatile a32 *a, a32 v, morder mo) {
+  GetFuzzingScheduler().SynchronizationPoint();
   SCOPED_ATOMIC(FetchSub, a, v, mo);
 }
 
 SANITIZER_INTERFACE_ATTRIBUTE
 a64 __tsan_atomic64_fetch_sub(volatile a64 *a, a64 v, morder mo) {
+  GetFuzzingScheduler().SynchronizationPoint();
   SCOPED_ATOMIC(FetchSub, a, v, mo);
 }
 
 #if __TSAN_HAS_INT128
 SANITIZER_INTERFACE_ATTRIBUTE
 a128 __tsan_atomic128_fetch_sub(volatile a128 *a, a128 v, morder mo) {
+  GetFuzzingScheduler().SynchronizationPoint();
   SCOPED_ATOMIC(FetchSub, a, v, mo);
 }
 #endif
 
 SANITIZER_INTERFACE_ATTRIBUTE
 a8 __tsan_atomic8_fetch_and(volatile a8 *a, a8 v, morder mo) {
+  GetFuzzingScheduler().SynchronizationPoint();
   SCOPED_ATOMIC(FetchAnd, a, v, mo);
 }
 
 SANITIZER_INTERFACE_ATTRIBUTE
 a16 __tsan_atomic16_fetch_and(volatile a16 *a, a16 v, morder mo) {
+  GetFuzzingScheduler().SynchronizationPoint();
   SCOPED_ATOMIC(FetchAnd, a, v, mo);
 }
 
 SANITIZER_INTERFACE_ATTRIBUTE
 a32 __tsan_atomic32_fetch_and(volatile a32 *a, a32 v, morder mo) {
+  GetFuzzingScheduler().SynchronizationPoint();
   SCOPED_ATOMIC(FetchAnd, a, v, mo);
 }
 
 SANITIZER_INTERFACE_ATTRIBUTE
 a64 __tsan_atomic64_fetch_and(volatile a64 *a, a64 v, morder mo) {
+  GetFuzzingScheduler().SynchronizationPoint();
   SCOPED_ATOMIC(FetchAnd, a, v, mo);
 }
 
 #if __TSAN_HAS_INT128
 SANITIZER_INTERFACE_ATTRIBUTE
 a128 __tsan_atomic128_fetch_and(volatile a128 *a, a128 v, morder mo) {
+  GetFuzzingScheduler().SynchronizationPoint();
   SCOPED_ATOMIC(FetchAnd, a, v, mo);
 }
 #endif
 
 SANITIZER_INTERFACE_ATTRIBUTE
 a8 __tsan_atomic8_fetch_or(volatile a8 *a, a8 v, morder mo) {
+  GetFuzzingScheduler().SynchronizationPoint();
   SCOPED_ATOMIC(FetchOr, a, v, mo);
 }
 
 SANITIZER_INTERFACE_ATTRIBUTE
 a16 __tsan_atomic16_fetch_or(volatile a16 *a, a16 v, morder mo) {
+  GetFuzzingScheduler().SynchronizationPoint();
   SCOPED_ATOMIC(FetchOr, a, v, mo);
 }
 
 SANITIZER_INTERFACE_ATTRIBUTE
 a32 __tsan_atomic32_fetch_or(volatile a32 *a, a32 v, morder mo) {
+  GetFuzzingScheduler().SynchronizationPoint();
   SCOPED_ATOMIC(FetchOr, a, v, mo);
 }
 
 SANITIZER_INTERFACE_ATTRIBUTE
 a64 __tsan_atomic64_fetch_or(volatile a64 *a, a64 v, morder mo) {
+  GetFuzzingScheduler().SynchronizationPoint();
   SCOPED_ATOMIC(FetchOr, a, v, mo);
 }
 
 #if __TSAN_HAS_INT128
 SANITIZER_INTERFACE_ATTRIBUTE
 a128 __tsan_atomic128_fetch_or(volatile a128 *a, a128 v, morder mo) {
+  GetFuzzingScheduler().SynchronizationPoint();
   SCOPED_ATOMIC(FetchOr, a, v, mo);
 }
 #endif
 
 SANITIZER_INTERFACE_ATTRIBUTE
 a8 __tsan_atomic8_fetch_xor(volatile a8 *a, a8 v, morder mo) {
+  GetFuzzingScheduler().SynchronizationPoint();
   SCOPED_ATOMIC(FetchXor, a, v, mo);
 }
 
 SANITIZER_INTERFACE_ATTRIBUTE
 a16 __tsan_atomic16_fetch_xor(volatile a16 *a, a16 v, morder mo) {
+  GetFuzzingScheduler().SynchronizationPoint();
   SCOPED_ATOMIC(FetchXor, a, v, mo);
 }
 
 SANITIZER_INTERFACE_ATTRIBUTE
 a32 __tsan_atomic32_fetch_xor(volatile a32 *a, a32 v, morder mo) {
   SCOPED_ATOMIC(FetchXor, a, v, mo);
 }
 
 SANITIZER_INTERFACE_ATTRIBUTE
 a64 __tsan_atomic64_fetch_xor(volatile a64 *a, a64 v, morder mo) {
+  GetFuzzingScheduler().SynchronizationPoint();
   SCOPED_ATOMIC(FetchXor, a, v, mo);
 }
 
 #if __TSAN_HAS_INT128
 SANITIZER_INTERFACE_ATTRIBUTE
 a128 __tsan_atomic128_fetch_xor(volatile a128 *a, a128 v, morder mo) {
+  GetFuzzingScheduler().SynchronizationPoint();
   SCOPED_ATOMIC(FetchXor, a, v, mo);
 }
 #endif
 
 SANITIZER_INTERFACE_ATTRIBUTE
 a8 __tsan_atomic8_fetch_nand(volatile a8 *a, a8 v, morder mo) {
+  GetFuzzingScheduler().SynchronizationPoint();
   SCOPED_ATOMIC(FetchNand, a, v, mo);
 }
 
 SANITIZER_INTERFACE_ATTRIBUTE
 a16 __tsan_atomic16_fetch_nand(volatile a16 *a, a16 v, morder mo) {
+  GetFuzzingScheduler().SynchronizationPoint();
   SCOPED_ATOMIC(FetchNand, a, v, mo);
 }
 
 SANITIZER_INTERFACE_ATTRIBUTE
 a32 __tsan_atomic32_fetch_nand(volatile a32 *a, a32 v, morder mo) {
+  GetFuzzingScheduler().SynchronizationPoint();
   SCOPED_ATOMIC(FetchNand, a, v, mo);
 }
 
 SANITIZER_INTERFACE_ATTRIBUTE
 a64 __tsan_atomic64_fetch_nand(volatile a64 *a, a64 v, morder mo) {
+  GetFuzzingScheduler().SynchronizationPoint();
   SCOPED_ATOMIC(FetchNand, a, v, mo);
 }
 
 #if __TSAN_HAS_INT128
 SANITIZER_INTERFACE_ATTRIBUTE
 a128 __tsan_atomic128_fetch_nand(volatile a128 *a, a128 v, morder mo) {
+  GetFuzzingScheduler().SynchronizationPoint();
   SCOPED_ATOMIC(FetchNand, a, v, mo);
 }
 #endif
 
 SANITIZER_INTERFACE_ATTRIBUTE
 int __tsan_atomic8_compare_exchange_strong(volatile a8 *a, a8 *c, a8 v,
     morder mo, morder fmo) {
+  GetFuzzingScheduler().SynchronizationPoint();
   SCOPED_ATOMIC(CAS, a, c, v, mo, fmo);
 }
 
 SANITIZER_INTERFACE_ATTRIBUTE
 int __tsan_atomic16_compare_exchange_strong(volatile a16 *a, a16 *c, a16 v,
     morder mo, morder fmo) {
+  GetFuzzingScheduler().SynchronizationPoint();
   SCOPED_ATOMIC(CAS, a, c, v, mo, fmo);
 }
 
 SANITIZER_INTERFACE_ATTRIBUTE
 int __tsan_atomic32_compare_exchange_strong(volatile a32 *a, a32 *c, a32 v,
     morder mo, morder fmo) {
+  GetFuzzingScheduler().SynchronizationPoint();
   SCOPED_ATOMIC(CAS, a, c, v, mo, fmo);
 }
 
 SANITIZER_INTERFACE_ATTRIBUTE
 int __tsan_atomic64_compare_exchange_strong(volatile a64 *a, a64 *c, a64 v,
     morder mo, morder fmo) {
+  GetFuzzingScheduler().SynchronizationPoint();
   SCOPED_ATOMIC(CAS, a, c, v, mo, fmo);
 }
 
 #if __TSAN_HAS_INT128
 SANITIZER_INTERFACE_ATTRIBUTE
 int __tsan_atomic128_compare_exchange_strong(volatile a128 *a, a128 *c, a128 v,
     morder mo, morder fmo) {
+  GetFuzzingScheduler().SynchronizationPoint();
   SCOPED_ATOMIC(CAS, a, c, v, mo, fmo);
 }
 #endif
 
 SANITIZER_INTERFACE_ATTRIBUTE
 int __tsan_atomic8_compare_exchange_weak(volatile a8 *a, a8 *c, a8 v,
     morder mo, morder fmo) {
+  GetFuzzingScheduler().SynchronizationPoint();
   SCOPED_ATOMIC(CAS, a, c, v, mo, fmo);
 }
 
 SANITIZER_INTERFACE_ATTRIBUTE
 int __tsan_atomic16_compare_exchange_weak(volatile a16 *a, a16 *c, a16 v,
     morder mo, morder fmo) {
+  GetFuzzingScheduler().SynchronizationPoint();
   SCOPED_ATOMIC(CAS, a, c, v, mo, fmo);
 }
 
 SANITIZER_INTERFACE_ATTRIBUTE
 int __tsan_atomic32_compare_exchange_weak(volatile a32 *a, a32 *c, a32 v,
     morder mo, morder fmo) {
+  GetFuzzingScheduler().SynchronizationPoint();
   SCOPED_ATOMIC(CAS, a, c, v, mo, fmo);
 }
 
 SANITIZER_INTERFACE_ATTRIBUTE
 int __tsan_atomic64_compare_exchange_weak(volatile a64 *a, a64 *c, a64 v,
     morder mo, morder fmo) {
+  GetFuzzingScheduler().SynchronizationPoint();
   SCOPED_ATOMIC(CAS, a, c, v, mo, fmo);
 }
 
 #if __TSAN_HAS_INT128
 SANITIZER_INTERFACE_ATTRIBUTE
 int __tsan_atomic128_compare_exchange_weak(volatile a128 *a, a128 *c, a128 v,
     morder mo, morder fmo) {
+  GetFuzzingScheduler().SynchronizationPoint();
   SCOPED_ATOMIC(CAS, a, c, v, mo, fmo);
 }
 #endif
 
 SANITIZER_INTERFACE_ATTRIBUTE
 a8 __tsan_atomic8_compare_exchange_val(volatile a8 *a, a8 c, a8 v,
     morder mo, morder fmo) {
+  GetFuzzingScheduler().SynchronizationPoint();
   SCOPED_ATOMIC(CAS, a, c, v, mo, fmo);
 }
 
 SANITIZER_INTERFACE_ATTRIBUTE
 a16 __tsan_atomic16_compare_exchange_val(volatile a16 *a, a16 c, a16 v,
     morder mo, morder fmo) {
+  GetFuzzingScheduler().SynchronizationPoint();
   SCOPED_ATOMIC(CAS, a, c, v, mo, fmo);
 }
 
 SANITIZER_INTERFACE_ATTRIBUTE
 a32 __tsan_atomic32_compare_exchange_val(volatile a32 *a, a32 c, a32 v,
     morder mo, morder fmo) {
+  GetFuzzingScheduler().SynchronizationPoint();
   SCOPED_ATOMIC(CAS, a, c, v, mo, fmo);
 }
 
 SANITIZER_INTERFACE_ATTRIBUTE
 a64 __tsan_atomic64_compare_exchange_val(volatile a64 *a, a64 c, a64 v,
     morder mo, morder fmo) {
+  GetFuzzingScheduler().SynchronizationPoint();
   SCOPED_ATOMIC(CAS, a, c, v, mo, fmo);
 }
 
 #if __TSAN_HAS_INT128
 SANITIZER_INTERFACE_ATTRIBUTE
 a128 __tsan_atomic128_compare_exchange_val(volatile a128 *a, a128 c, a128 v,
     morder mo, morder fmo) {
+  GetFuzzingScheduler().SynchronizationPoint();
   SCOPED_ATOMIC(CAS, a, c, v, mo, fmo);
 }
 #endif
 
 SANITIZER_INTERFACE_ATTRIBUTE
 void __tsan_atomic_thread_fence(morder mo) {
+  GetFuzzingScheduler().SynchronizationPoint();
   char* a = 0;
   SCOPED_ATOMIC(Fence, mo);
 }
 
 SANITIZER_INTERFACE_ATTRIBUTE
 void __tsan_atomic_signal_fence(morder mo) {
 }
 }  // extern "C"
if (thr->ignore_sync) { \
       (ret) = Atomic##func(thr, pc, __VA_ARGS__); \
       FuncExit(thr); \
     } \
 /**/
 
 extern "C" {
 SANITIZER_INTERFACE_ATTRIBUTE
 void __tsan_go_atomic32_load(ThreadState *thr, uptr cpc, uptr pc, u8 *a) {
+  GetFuzzingScheduler().SynchronizationPoint();
   ATOMIC_RET(Load, *(a32*)(a+8), *(a32**)a, mo_acquire);
 }
 
 SANITIZER_INTERFACE_ATTRIBUTE
 void __tsan_go_atomic64_load(ThreadState *thr, uptr cpc, uptr pc, u8 *a) {
+  GetFuzzingScheduler().SynchronizationPoint();
   ATOMIC_RET(Load, *(a64*)(a+8), *(a64**)a, mo_acquire);
 }
 
 SANITIZER_INTERFACE_ATTRIBUTE
 void __tsan_go_atomic32_store(ThreadState *thr, uptr cpc, uptr pc, u8 *a) {
+  GetFuzzingScheduler().SynchronizationPoint();
   ATOMIC(Store, *(a32**)a, *(a32*)(a+8), mo_release);
 }
 
 SANITIZER_INTERFACE_ATTRIBUTE
 void __tsan_go_atomic64_store(ThreadState *thr, uptr cpc, uptr pc, u8 *a) {
+  GetFuzzingScheduler().SynchronizationPoint();
   ATOMIC(Store, *(a64**)a, *(a64*)(a+8), mo_release);
 }
 
 SANITIZER_INTERFACE_ATTRIBUTE
 void __tsan_go_atomic32_fetch_add(ThreadState *thr, uptr cpc, uptr pc, u8 *a) {
+  GetFuzzingScheduler().SynchronizationPoint();
   ATOMIC_RET(FetchAdd, *(a32*)(a+16), *(a32**)a, *(a32*)(a+8), mo_acq_rel);
 }
 
 SANITIZER_INTERFACE_ATTRIBUTE
 void __tsan_go_atomic64_fetch_add(ThreadState *thr, uptr cpc, uptr pc, u8 *a) {
+  GetFuzzingScheduler().SynchronizationPoint();
   ATOMIC_RET(FetchAdd, *(a64*)(a+16), *(a64**)a, *(a64*)(a+8), mo_acq_rel);
 }
 
 SANITIZER_INTERFACE_ATTRIBUTE
 void __tsan_go_atomic32_exchange(ThreadState *thr, uptr cpc, uptr pc, u8 *a) {
+  GetFuzzingScheduler().SynchronizationPoint();
   ATOMIC_RET(Exchange, *(a32*)(a+16), *(a32**)a, *(a32*)(a+8), mo_acq_rel);
 }
 
 SANITIZER_INTERFACE_ATTRIBUTE
 void __tsan_go_atomic64_exchange(ThreadState *thr, uptr cpc, uptr pc, u8 *a) {
+  GetFuzzingScheduler().SynchronizationPoint();
   ATOMIC_RET(Exchange, *(a64*)(a+16), *(a64**)a, *(a64*)(a+8), mo_acq_rel);
 }
 
 SANITIZER_INTERFACE_ATTRIBUTE
 void __tsan_go_atomic32_compare_exchange(
     ThreadState *thr, uptr cpc, uptr pc, u8 *a) {
+  GetFuzzingScheduler().SynchronizationPoint();
   a32 cur = 0;
   a32 cmp = *(a32*)(a+8);
   ATOMIC_RET(CAS, cur, *(a32**)a, cmp, *(a32*)(a+12), mo_acq_rel, mo_acquire);
   *(bool*)(a+16) = (cur == cmp);
 }
 
 SANITIZER_INTERFACE_ATTRIBUTE
 void __tsan_go_atomic64_compare_exchange(
     ThreadState *thr, uptr cpc, uptr pc, u8 *a) {
+  GetFuzzingScheduler().SynchronizationPoint();
   a64 cur = 0;
   a64 cmp = *(a64*)(a+8);
   ATOMIC_RET(CAS, cur, *(a64**)a, cmp, *(a64*)(a+16), mo_acq_rel, mo_acquire);
   *(bool*)(a+24) = (cur == cmp);
 }
 }  // extern "C"
 #endif  // #if !SANITIZER_GO