I've got an old problem with clamd, which creates a bunch of threads. Every so often the logs will show e.g.,
Jul 31 06:01:41 mx1 clamd[24070]: pthread_create failed Jul 31 06:01:41 mx1 clamd[24070]: pthread_create failed Jul 31 06:01:41 mx1 clamd[24070]: pthread_create failed Jul 31 06:01:41 mx1 clamd[24070]: pthread_create failed It doesn't cause any noticeable problems, so I've sort of left it alone but tonight I dug in a little. The problem seems (somehow) related to that box's hardening. I'm using a test program that creates a bunch of threads and then just kills them. On the box in question, # uname -a Linux mx1 3.4.2-hardened #1 SMP Wed Jul 11 13:41:57 EDT 2012 i686 Intel(R) Xeon(TM) CPU 3.06GHz GenuineIntel GNU/Linux # ./pthread_test 25 Creating 25 threads Created thread #0... Created thread #1... Created thread #2... Created thread #3... pthread_create failed: Resource temporarily unavailable Disabling all paxctl protections helps, but doesn't allow me to get all the way to 25. I tried doing the protections one-at-a-time; it doesn't really help: # paxctl -pemrxs pthread_test # ./pthread_test 25 Creating 25 threads Created thread #0... Created thread #1... Created thread #2... Created thread #3... Created thread #4... Created thread #5... Created thread #6... Created thread #7... Created thread #8... Created thread #9... pthread_create failed: Resource temporarily unavailable I get nothing in my dmesg, which otherwise records most limit-based denials. Is there some way I can troubleshoot this? It works on amd64 with the same kernel hardening options.
