Re: [PATCH] net: Revert "net_sched: no need to free qdisc in RCU callback"
flat view
From: Cong Wang <hidden>
Date: 2017-12-21 21:00:17
On Thu, Dec 21, 2017 at 12:39 AM, Jiri Pirko [off-list ref] wrote:
Why just moving qdisc_free to rcu is not enough? It would resolve this issue and also avoid using synchronize net. Something like:
If you mean Jakub's issue, apparently not: https://www.kernel.org/pub/linux/kernel/people/paulmck/Answers/RCU/RCUCBordering.html Jiri, you have to use a rcu barrier to wait for a rcu callback, not queuing another rcu callback, the ordering is simply NOT guaranteed. What's more importantly, you already have one rcu barrier in the same function. Why keep believing you don't need it?