Messages in this thread | | | Date | Sun, 8 Oct 2023 10:56:09 -0700 | From | Cong Wang <> | Subject | Re: [PATCH] net/sched: use spin_lock_bh() on &gact->tcf_lock |
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On Thu, Oct 05, 2023 at 05:01:07PM +0800, Chengfeng Ye wrote: > Hi Jakub, > > Thanks for the reply, > > I inspected the code a bit more, it seems that the TC action is called from > tcf_proto_ops.classify() callback, which is called from Qdisc_ops enqueue > callback. > > Then Qdisc enqueue callback is from > > -> __dev_queue_xmit() > -> __dev_xmit_skb() > -> dev_qdisc_enqueue() > > inside the net core. It seems that this __dev_queue_xmit() callback is > typically called from BH context (e.g., NET_TX_SOFTIRQ) with BH > already disabled, but sometimes also can from a work queue under > process context, one case is the br_mrp_test_work_expired() inside > net/bridge/br_mrp.c. Does it indicate that this TC action could also be > called with BH enable? I am not a developer so really not sure about it, > as the networking code is a bit long and complicated.
Doesn't __dev_queue_xmit() itself disable BH with rcu_read_lock_bh()??
Thanks.
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