This commit makes the ltp cpuctl latency test #2 hang indefinitely: commit b5d9d734a53e0204aab0089079cbde2a1285a38f Author: Mike Galbraith Date: Tue Sep 8 11:12:28 2009 +0200 sched: Ensure that a child can't gain time over it's parent after fork() When I revert this commit the test progresses as it did in 2.6.31. I have seen this issue on 2.6.32 and 2.6.32.19. The hang goes away in 2.6.33 starting with this commit: commit 88ec22d3edb72b261f8628226cd543589a6d5e1b Author: Peter Zijlstra Date: Wed Dec 16 18:04:41 2009 +0100 sched: Remove the cfs_rq dependency from set_task_cpu() Even though this appears to be resolved in 2.6.33, I am reporting it because 2.6.32 is the "long-term stable release". My test system is a single socket dual core amd - model name : Dual Core AMD Opteron(tm) Processor 180 with 4GB of RAM. Kernel config file attached. The issue is easily reproducible for me by downloading and building ltp, then running testcases/kernel/controllers/cpuctl/run_cpuctl_latency_test.sh 2 Please let me know if you need any other information to help reproduce this issue. Thanks Josh