[Pdns-users] Possible tcp listener issue
Brad.Dameron at clearwire.com
Tue Jun 29 05:55:07 UTC 2010
> -----Original Message-----
> So far, Josh & Simon are the only ones reporting this issue though, so
> something must be going on. What Laurent Papier reported has been
> already (although he may not know it yet ;-))
We're able to reproduce what may be this same TCP listener issue that is
being discussed on the email list with little effort, using the latest
3.3 pre-release code.
We use the queryfile-example-3million file from nominum :
and the script below to fire off a flood of TCP requests, 1000 at a
Within a few minutes, pdns_recursor locks up and refuses to answer any
more TCP queries. UDP continues fine. Our last run, it queried only 16K
addresses before hanging.
Environment is a HP G6 blade running CentOS 5.1 Linux:
# uname -a
Linux MOC-LAB001-HPB-DNS-NTP-1 2.6.18-53.1.14.el5 #1 SMP Wed Mar 5
11:37:38 EST 2008 x86_64 x86_64 x86_64 GNU/Linux
Invoked with the following arguments:
--allow-from= --max-cache-entries=3000000 --log-common-errors=no
--threads=4 --socket-dir=/var/run/recursor1 --daemon --dont-query=
zcat queryfile-example-3million.gz | while read x ; do
if [ $n -le $MAX ] ; then
print "dig @127.0.0.1 +tcp +short $x >> out 2>>out.err
# genrun.sh > run
# sh ./run &
# Use the following script to monitor progress:
# while : ; do
# nt=$(rec_control --socket-dir=/var/run/recursor1 get
# nl=$(netstat -an|grep :53|grep -v LISTEN|wc -l)
# print "$nt queries $nl open"
# sleep 5
These errors were noted in the logs:
pdns_recursor: segfault at 00007ffefffffff8 rip 0000000000455740
rsp 00002aaaaaaecbb0 error 4
pdns_recursor general protection rip:455740 rsp:2aaaaaaecbb0
Let us know if you have any new patches to test!
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