BIND 10 #684: b10-xfrout uses 100% of CPU

[BIND 10 Development]

#684: b10-xfrout uses 100% of CPU
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                 Reporter:  shane     |                Owner:
                     Type:  defect    |               Status:  new
                 Priority:  critical  |            Milestone:
                Component:  xfrout    |           Resolution:
                 Keywords:            |            Sensitive:  0
Estimated Number of Hours:  0.0       |  Add Hours to Ticket:  0
                Billable?:  1         |          Total Hours:  0
                Internal?:  0         |
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Changes (by shane):

 * priority:  major => critical


Comment:

 I had a look at this today, as it is affecting my server. strace on the
 offending thread reveals:

 {{{
 select(14, [10 12 13], [], [], {0, 0})  = 0 (Timeout)
 gettimeofday({1301656680, 878097}, NULL) = 0
 gettimeofday({1301656680, 878149}, NULL) = 0
 gettimeofday({1301656680, 878221}, NULL) = 0
 select(14, [10 12 13], [], [], {0, 0})  = 0 (Timeout)
 gettimeofday({1301656680, 878369}, NULL) = 0
 gettimeofday({1301656680, 878421}, NULL) = 0
    .
    .
    .
 }}}

 I looked through the code and the only select() call that seems to match
 is this one from the notify code:

 {{{
         (block_timeout, valid_socks, notifying_zones) = \
             self._prepare_select_info()
         # This is None only during some tests
         if self._read_sock is not None:
             valid_socks.append(self._read_sock)
         try:
             r_fds, w, e = select.select(valid_socks, [], [],
 block_timeout)
         except select.error as err:
             if err.args[0] != EINTR:
                 return {}, {}
 }}}

 The block_timeout is getting set to 0 for some reason. This may have to do
 with errors sending because it is trying to use IPv6 as notify targets.

-- 
Ticket URL: <https://bind10.isc.org/ticket/684#comment:3>
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