HDFS-12494. libhdfs SIGSEGV in setTLSExceptionStrings. Contributed by John Zhuge.

hadoop-hdfs-project/hadoop-hdfs-native-client/src/main/native/libhdfs/jni_helper.c

@@ -522,19 +522,21 @@ JNIEnv* getJNIEnv(void)
     /* Create a ThreadLocalState for this thread */
     state = threadLocalStorageCreate();
     if (!state) {
+      mutexUnlock(&jvmMutex);
       fprintf(stderr, "getJNIEnv: Unable to create ThreadLocalState\n");
       return NULL;
     }
-    state->env = getGlobalJNIEnv();
-    mutexUnlock(&jvmMutex);
-    if (!state->env) {
-      goto fail;
-    }
     if (threadLocalStorageSet(state)) {
+      mutexUnlock(&jvmMutex);
       goto fail;
     }
     THREAD_LOCAL_STORAGE_SET_QUICK(state);
 
+    state->env = getGlobalJNIEnv();
+    mutexUnlock(&jvmMutex);
+    if (!state->env) {
+      goto fail;
+    }
     return state->env;
 
 fail: