Use LINKER_INITIALIZED for mutexes with static storage class.

This was causing exit-time races as some threads were accessing the
mutex as it was being destructed.

			---------------

It is illegal to use any static type with a constructor/destructor with static
storage class in a multithreaded C++ programme that can exit(), even if the
constructor is protected by C++11's function-scope static initialization rules,
because exit-time destruction is unsafe in the presence of multiple threads.

For things that are not function-scope, the construction is also unsafe,
because global contruction ordering is undefined in general.

The LINKER_INITIALIZED variant constructor for TensorFlow's mutex avoids these
problems, at the cost of relying on the linker to zero-initialize the BSS
region.

PiperOrigin-RevId: 176612772

1 files changed, 1 insertions, 1 deletions

diff --git a/tensorflow/core/framework/op_def_util.cc b/tensorflow/core/framework/op_def_util.cc
index f7d4166f97..29feda499f 100644
--- a/tensorflow/core/framework/op_def_util.cc
+++ b/tensorflow/core/framework/op_def_util.cc
@@ -332,7 +332,7 @@ Status CheckOpDeprecation(const OpDef& op_def, int graph_def_version) {
           ". ", dep.explanation(), ".");
     } else {
       // Warn only once for each op name, and do it in a threadsafe manner.
-      static mutex mu;
+      static mutex mu(LINKER_INITIALIZED);
       static std::unordered_set<string> warned;
       bool warn;
       {