One solution to fix this problem is to use pthread_sigmask() on the _read() thread to not handle SIGARLM. For example, the faulthandler uses the following code to not handle any thread in its timeout thread:

#ifdef HAVE_PTHREAD_H
    sigset_t set;

    /* we don't want to receive any signal */
    sigfillset(&set);
#if defined(HAVE_PTHREAD_SIGMASK) && !defined(HAVE_BROKEN_PTHREAD_SIGMASK)
    pthread_sigmask(SIG_SETMASK, &set, NULL);
#else
    sigprocmask(SIG_SETMASK, &set, NULL);
#endif
#endif