| 1 |
I've got an old problem with clamd, which creates a bunch of threads. |
| 2 |
Every so often the logs will show e.g., |
| 3 |
|
| 4 |
Jul 31 06:01:41 mx1 clamd[24070]: pthread_create failed |
| 5 |
Jul 31 06:01:41 mx1 clamd[24070]: pthread_create failed |
| 6 |
Jul 31 06:01:41 mx1 clamd[24070]: pthread_create failed |
| 7 |
Jul 31 06:01:41 mx1 clamd[24070]: pthread_create failed |
| 8 |
|
| 9 |
It doesn't cause any noticeable problems, so I've sort of left it alone |
| 10 |
but tonight I dug in a little. The problem seems (somehow) related to |
| 11 |
that box's hardening. |
| 12 |
|
| 13 |
I'm using a test program that creates a bunch of threads and then just |
| 14 |
kills them. On the box in question, |
| 15 |
|
| 16 |
# uname -a |
| 17 |
Linux mx1 3.4.2-hardened #1 SMP Wed Jul 11 13:41:57 EDT 2012 i686 |
| 18 |
Intel(R) Xeon(TM) CPU 3.06GHz GenuineIntel GNU/Linux |
| 19 |
# ./pthread_test 25 |
| 20 |
Creating 25 threads |
| 21 |
Created thread #0... |
| 22 |
Created thread #1... |
| 23 |
Created thread #2... |
| 24 |
Created thread #3... |
| 25 |
pthread_create failed: Resource temporarily unavailable |
| 26 |
|
| 27 |
Disabling all paxctl protections helps, but doesn't allow me to get all |
| 28 |
the way to 25. I tried doing the protections one-at-a-time; it doesn't |
| 29 |
really help: |
| 30 |
|
| 31 |
# paxctl -pemrxs pthread_test |
| 32 |
# ./pthread_test 25 |
| 33 |
Creating 25 threads |
| 34 |
Created thread #0... |
| 35 |
Created thread #1... |
| 36 |
Created thread #2... |
| 37 |
Created thread #3... |
| 38 |
Created thread #4... |
| 39 |
Created thread #5... |
| 40 |
Created thread #6... |
| 41 |
Created thread #7... |
| 42 |
Created thread #8... |
| 43 |
Created thread #9... |
| 44 |
pthread_create failed: Resource temporarily unavailable |
| 45 |
|
| 46 |
I get nothing in my dmesg, which otherwise records most limit-based denials. |
| 47 |
|
| 48 |
Is there some way I can troubleshoot this? It works on amd64 with the |
| 49 |
same kernel hardening options. |
Archives