Remove check except.

Author: trivialfis

rabit/include/rabit/internal/socket.h

@@ -609,14 +609,6 @@ struct PollHelper {
     const auto& pfd = fds.find(fd);
     return pfd != fds.end() && ((pfd->second.events & POLLOUT) != 0);
   }
-  /*!
-   * \brief Check if the descriptor has any exception
-   * \param fd file descriptor to check status
-   */
-  inline bool CheckExcept(SOCKET fd) const {
-    const auto& pfd = fds.find(fd);
-    return pfd != fds.end() && ((pfd->second.events & POLLPRI) != 0);
-  }
 
   /*!
    * \brief peform poll on the set defined, read, write, exception

rabit/src/allreduce_base.cc

@@ -724,13 +724,6 @@ AllreduceBase::TryBroadcast(void *sendrecvbuf_, size_t total_size, int root) {
     if (finished) break;
     // select
     watcher.Poll(timeout_sec);
-    // exception handling
-    for (int i = 0; i < nlink; ++i) {
-      // recive OOB message from some link
-      if (watcher.CheckExcept(links[i].sock)) {
-        return ReportError(&links[i], kGetExcept);
-      }
-    }
     if (in_link == -2) {
       // probe in-link
       for (int i = 0; i < nlink; ++i) {