Re: [Patch net v3 3/3] net_sched: carefully handle tcf_block_put()

2017-09-12 Thread Jiri Pirko
Tue, Sep 12, 2017 at 01:33:32AM CEST, xiyou.wangc...@gmail.com wrote: >As pointed out by Jiri, there is still a race condition between >tcf_block_put() and tcf_chain_destroy() in a RCU callback. There >is no way to make it correct without proper locking or synchronization, >because both operate on

[Patch net v3 3/3] net_sched: carefully handle tcf_block_put()

2017-09-11 Thread Cong Wang
As pointed out by Jiri, there is still a race condition between tcf_block_put() and tcf_chain_destroy() in a RCU callback. There is no way to make it correct without proper locking or synchronization, because both operate on a shared list. Locking is hard, because the only lock we can pick here