Hello, Jiri. On Thu, Mar 17, 2016 at 01:00:13PM +0100, Jiri Slaby wrote: > >> I have not done that yet, but today, I see: > >> destroy_workqueue: name='req_hci0' pwq=ffff88002f590300 > >> wq->dfl_pwq=ffff88002f591e00 pwq->refcnt=2 pwq->nr_active=0 delayed_works: > >> pwq 12: cpus=0-1 node=0 flags=0x4 nice=-20 active=0/1 > >> in-flight: 18568:wq_barrier_func > > > > So, this means that there's flush_work() racing against workqueue > > destruction, which can't be safe. :( > > But I cannot trigger the WARN_ONs in the attached patch, so I am > confused how this can happen :(. (While I am still seeing the destroy > WARNINGs.)
So, no operations should be in progress when destroy_workqueue() is called. If somebody was flushing a work item, the flush call must have returned before destroy_workqueue() was invoked, which doesn't seem to be the case here. Can you trigger BUG_ON() or sysrq-t when the above triggers? There must be a task which is flushing a work item there and it shouldn't be difficult to pinpoint what's going on from it. Thanks. -- tejun
