Messages in this thread | | | Subject | Re: [PATCH] avoid race condition in pick_next_task_fair in kernel/sched_fair.c | From | Peter Zijlstra <> | Date | Thu, 23 Dec 2010 13:12:10 +0100 |
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On Thu, 2010-12-23 at 10:08 +0800, Yong Zhang wrote: > > systemd--1251 0d..5. 2015398us : enqueue_task_fair <-enqueue_task > > systemd--1251 0d..5. 2015398us : print_runqueue <-enqueue_task_fair > > systemd--1251 0d..5. 2015399us : __print_runqueue: cfs_rq: c2407c34, nr: 3, load: 3072 > > systemd--1251 0d..5. 2015400us : __print_runqueue: curr: f6a8de5c, comm: systemd-cgroups/1251, load: 1024 > > systemd--1251 0d..5. 2015401us : __print_runqueue: se: f69e6300, load: 1024, > > systemd--1251 0d..5. 2015401us : __print_runqueue: cfs_rq: f69e6540, nr: 2, load: 2048 > > systemd--1251 0d..5. 2015402us : __print_runqueue: curr: (null) > > systemd--1251 0d..5. 2015402us : __print_runqueue: se: f69e65a0, load: 4137574976, > > the load == f69e65a0 == address of se, odd
This appears to be consistently true, I've also found that in between these two prints, there is a free_sched_group() freeing that exact entry. So post-print is a use-after-free artifact.
What's interesting is that its freeing a cfs_rq struct with nr_running=1, that should not be possible...
/me goes stare at the whole cgroup task attach vs cgroup destruction muck.
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