tsan: improve "read unlock of a write locked mutex" report

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@207208 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 21 insertions, 4 deletions

diff --git a/lib/tsan/rtl/tsan_report.cc b/lib/tsan/rtl/tsan_report.cc
index 6875c4cad..98a7d0f4d 100644
--- a/lib/tsan/rtl/tsan_report.cc
+++ b/lib/tsan/rtl/tsan_report.cc
@@ -78,6 +78,8 @@ static const char *ReportTypeString(ReportType typ) {
     return "double lock of a mutex";
   if (typ == ReportTypeMutexBadUnlock)
     return "unlock of an unlocked mutex (or by a wrong thread)";
+  if (typ == ReportTypeMutexBadReadUnlock)
+    return "read unlock of a write locked mutex";
   if (typ == ReportTypeSignalUnsafe)
     return "signal-unsafe call inside of a signal";
   if (typ == ReportTypeErrnoInSignal)
diff --git a/lib/tsan/rtl/tsan_report.h b/lib/tsan/rtl/tsan_report.h
index 5b643351b..7c14eff18 100644
--- a/lib/tsan/rtl/tsan_report.h
+++ b/lib/tsan/rtl/tsan_report.h
@@ -26,6 +26,7 @@ enum ReportType {
   ReportTypeMutexDestroyLocked,
   ReportTypeMutexDoubleLock,
   ReportTypeMutexBadUnlock,
+  ReportTypeMutexBadReadUnlock,
   ReportTypeSignalUnsafe,
   ReportTypeErrnoInSignal,
   ReportTypeDeadlock
diff --git a/lib/tsan/rtl/tsan_rtl_mutex.cc b/lib/tsan/rtl/tsan_rtl_mutex.cc
index 4f6a2d09b..ae6e4f798 100644
--- a/lib/tsan/rtl/tsan_rtl_mutex.cc
+++ b/lib/tsan/rtl/tsan_rtl_mutex.cc
@@ -249,18 +249,32 @@ void MutexReadUnlock(ThreadState *thr, uptr pc, uptr addr) {
   SyncVar *s = ctx->synctab.GetOrCreateAndLock(thr, pc, addr, true);
   thr->fast_state.IncrementEpoch();
   TraceAddEvent(thr, thr->fast_state, EventTypeRUnlock, s->GetId());
+  bool report_bad_unlock = false;
   if (s->owner_tid != SyncVar::kInvalidTid) {
-    Printf("ThreadSanitizer WARNING: read unlock of a write locked mutex %p\n",
-           addr);
-    PrintCurrentStack(thr, pc);
+    if (flags()->report_mutex_bugs && !s->is_broken) {
+      s->is_broken = true;
+      report_bad_unlock = true;
+    }
   }
   ReleaseImpl(thr, pc, &s->read_clock);
   if (flags()->detect_deadlocks && s->recursion == 0) {
     Callback cb(thr, pc);
     ctx->dd->MutexBeforeUnlock(&cb, &s->dd, false);
   }
+  u64 mid = s->GetId();
   s->mtx.Unlock();
-  thr->mset.Del(s->GetId(), false);
+  // Can't touch s after this point.
+  thr->mset.Del(mid, false);
+  if (report_bad_unlock) {
+    ThreadRegistryLock l(ctx->thread_registry);
+    ScopedReport rep(ReportTypeMutexBadReadUnlock);
+    rep.AddMutex(mid);
+    StackTrace trace;
+    trace.ObtainCurrent(thr, pc);
+    rep.AddStack(&trace);
+    rep.AddLocation(addr, 1);
+    OutputReport(ctx, rep);
+  }
   if (flags()->detect_deadlocks) {
     Callback cb(thr, pc);
     ReportDeadlock(thr, pc, ctx->dd->GetReport(&cb));