On Mon, Jun 13, 2022 at 2:35 PM Satya Durga Srinivasu Prabhala <quic_satyap@xxxxxxxxxxx> wrote: > > > On 6/13/22 2:01 PM, Alexei Starovoitov wrote: > > is doesn't solve anything. > > Please provide a reproducer. > > I'm trying to find an easy way to repro the issue, so far, unsuccessful. > > > iirc the task's affinity change can race even with preemption disabled > > on this cpu. Why would s/migrate/preemption/ address the deadlock ? > > I don't think task's affinity change races with preemption disabled/enabled. > > Switching to preemption disable/enable calls helps as it's just simple > counter increment and decrement with a barrier, but with migrate > disable/enable when task's affinity changes, we run into recursive bug > due to rq lock. As Yonghong already explained, replacing migrate_disable with preempt_disable around bpf prog invocation is not an option.
