Seeing issue with BIO_free call

Hi,

I'm encountering an issue with the `BIO_free` call in the following code
snippet.

When `sslCleanupTask` is triggered and `BIO_free` is called, we
occasionally receive data on `listen_s`. This subsequently causes a hang
because `BIO_do_accept` in `sslListenTask` is then called on a file
descriptor that has already been freed or closed by `BIO_free`.

Could you please explain why `listen_s` is set in `readfds` when `BIO_free`
is called?
I've attempted to set the `BIO_CLOSE` flag, but the issue persists.

Do we need to set any other APIs or flags to prevent this? Please note that
we are not initiating any connections here.

*sslListenTask()*
*{*
*    BIO *ppBio = NULL;*

*    if ((ppBio = BIO_new_accept("[::]:443")) == NULL)*
*    {*
*      BIO_free(ppBio);*
*      return;*
*    }*
*    BIO_set_bind_mode(ppBio, BIO_BIND_REUSEADDR);*
*    /* First call sets up the BIO listening socket */*
*    if (BIO_do_accept(ppBio) <= NULL)*
*    {*
*      BIO_free(ppBio);*
*      return;*
*    }*
*    if( (listen_s = BIO_get_fd(ppBio,0)) <=0 )*
*    {*
*       BIO_free(ppBio);*
*        return;*
*    }*
*   /**
*    ** Loop waiting for SSLT connections*
*    */*
*    while (1)*
*    {*
*      fd_set readfds;*
*      struct timeval tmout;*
*      int num,max_fd;*

*      tmout.tv_sec = 3;*
*      tmout.tv_usec = 0;*
*      FD_ZERO(&readfds);*
*      FD_SET(listen_s,&readfds);*
*      max_fd = listen_s;*

*      num = select(max_fd + 1, &readfds, NULL, NULL, &tmout);*

*      if (num <= 0)*
*      {*
*        if (!((num < 0) && (EINTR == errno)))*
*        {*
*          /* Set cancellation point for timeout and other errors except
EINTR */*
*          pthread_testcancel();*
*        }*

*      continue;*
*    }*
*     if (FD_ISSET(listen_s, &readfds))*
*     {*
*        if (BIO_do_accept(rdy_acc) <= L7_NULL)*
*       {*
*          //err*
*       }*

*      client = BIO_pop(rdy_acc);*
*      //Rest of the program for SSL*
*   } *
* } /* while */*
*}*

*There is one more task doing the BIO_free if the SSL port changes.*
*sslCleanupTask()*
*{*
*   BIO_free(ppBio);*
*}*

Thanks & Regards,
Samiya khanum

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