Re: [libmicrohttpd] Extra worker thread on failed daemon start

[Christian Grothoff]

Hi!

You're totally right, fixed in SVN 35728.

-Christian

On 05/13/2015 04:47 AM, Jared Cantwell wrote:
> Hey,
> 
> I'm debugging a problem with a crash in MHD_select_thread.  We had
> MHD_start_daemon_va fail while creating worker threads with the following
> error: "file descriptor for worker control pipe exceeds maximum value".  We
> know what caused this error and are fixing it.  But the problem was that a
> MHD_select_thread worker thread was left running in the background after
> MHD_start_daemon_va returned failure.  I think the problem is from this
> code in the thread_failed case in daemon.c:
> 
>   /* Shutdown worker threads we've already created. Pretend
>      as though we had fully initialized our daemon, but
>      with a smaller number of threads than had been
>      requested. */
>   daemon->worker_pool_size = i - 1;
>   MHD_stop_daemon (daemon);
>   return NULL;
> 
> From the code, it looks like "i" is actually the number of threads that
> were successfully created, so the "i - 1" in this code will leave an extra
> thread hanging since MHD_stop_daemon will clean up one less thread than it
> should.  I'll probably try to work up a test to verify removing the "- 1"
> is correct, but that could take me some time so I wanted to make sure I
> wasn't missing something obvious before heading down that path.
> 
> ~Jared
>