[Samba] CPU consumption of samba rises to 100%

Ali Fahimi ar.fahimi at gmail.com
Tue Jun 26 13:38:35 UTC 2018


CPU consumption of samba rises to 100%

I am doing Achilles tests on a Linux-based server. I have noticed that
during certain tests (and UDP port discovery), the temperature of the CPU
cores surges to around 80-90 °C which causes the CPU clock to throttle and
renders the server practically unresponsive.

Following closer investigations, we found out that there is a direct link
between the rise of CPU consumption by a certain process and the CPU
temperature. In our case, the concerned process is Samba

We are using samba4 in the full active directory mode.

Environment details:

OS: Ubuntu 14.04 LTS

Samba version: 4.3.11

In our environment, there is a direct connection between the server running
Samba and the test PC; no other element in the network.

As far as we understand, this looks like a DoS attack. Certain tests render
the server completely unresponsive.

Is this a known issue? If yes, is there a fix for it?

Thank you in advance,

Ali Fahimi
Montpellier, France

Please consider the environment before printing.

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