[ntp:questions] Re: ACTS - too many recvbufs allocated (40) (Correct the Version of ntp-dev)

Ronan Flood ronan at noc.ulcc.ac.uk
Mon Feb 7 22:17:47 UTC 2005

cipo <cseplo_l at netlock.net> wrote:

> Without C1->C0 change in the modem initialization string (for the 
> Europian time services of course) the serial port return 0 bytes.
> In ntp_io.c/void input_handler(l_fp *cts)
> select(maxactivefd+1,...) triggered,
> ...
> rb=get_free_recv_buffer(); buffer allocated
> ...
> rb->recv_length=read(fd,...); read 0 bytes !!!
> if(rb->recv_length == -1) {
>     handled as error, buffer released.
> }
> But in the case of rb->recv_length=0, buffer remains allocated, 
> select(...) triggered again, (in ntpd.c/service_main too)  reading 0 
> bytes again, 40 times, then the message in the subject appears. If the 
> rb->recv_length=0 handled as above (buffer released, goto select_again) 

"continue" is probably a better move than "goto select_again",
but that's a minor point.

> than there is an infinite loop with 100% proc consumed. Another approach 
> is required.
> If C0 patch applied, this not happens.
> I don't now the correct solution yet.

Sounds like a hangup.  Do you have anything connected to the DSR line
of the serial port?  If so, you could try disconnecting that; which
should leave CLOCAL set on the port so that hangups are ignored -- see

                      Ronan Flood <R.Flood at noc.ulcc.ac.uk>
                        working for but not speaking for
             Network Services, University of London Computer Centre
     (which means: don't bother ULCC if I've said something you don't like)

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