libresolv.so.2 Exhausts Swap File Space With Multithreaded Applications When DNS is Specified in /etc/nsswitch.conf (4646349)

If DNS is specified for hosts or ipnodes lookup in the /etc/nsswitch.conf file, and your system is running multithreaded applications, the nscd daemon might crash. This problem occurs because the nscd daemon slowly grows in size, and can consume up to 4 Gbytes of swap space. If all swap space becomes exhausted, then nscd might crash, and other new processes might suffer from various random errors.

Workaround: To avoid this problem, modify the nscd settings by following these steps.

1. Become superuser.

2. Stop the nscd daemon.

   # /etc/init.d/nscd stop

3. Add or modify the following lines in the /etc/nscd.conf file.

   • keep-hot-count hosts 0

   • keep-hot-count ipnodes 0

4. Restart the nscd daemon.

   # /etc/init.d/nscd start

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   Note -

   Not running the nscd will cause the same leak to appear in any multithreaded applications doing host lookups.

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