On Apr 19 2024, Alexei Starovoitov wrote: > On Fri, Apr 19, 2024 at 8:12 AM Benjamin Tissoires <bentiss@xxxxxxxxxx> wrote: > > > > > > It's something I added while adding the tests. And some tests were passing > > in case I was having a non sleepable callback. But if we have > > bpf_rcu_read_lock(), we are all fine and can reduce the complexity. > > Not quite following what was the issue. > Since the verifier is unconditionally verifying such callback as sleepable > the callback won't be able to access rcu pointers without doing > explicit bpf_rcu_read_lock() first (and few other code patterns > might be rejected), but that's a good thing. Oh, I missed that. Well, given that the verifier enforces everything, I guess we are good :) > Maybe next to set_cb kfunc add a comment that wq callbacks are sleepable. > I think bpf prog writers are often with kernel background, > so it will be their natural assumption that cb is sleepable. I assume so as well. Cheers, Benjamin
