On Wed, Nov 16, 2022 at 7:16 PM Joel Fernandes (Google) <joel@xxxxxxxxxxxxxxxxx> wrote: > > In a networking test on ChromeOS, we find that using the new CONFIG_RCU_LAZY > causes a networking test to fail in the teardown phase. > > The failure happens during: ip netns del <name> > > Using ftrace, I found the callbacks it was queuing which this series fixes. Use > call_rcu_flush() to revert to the old behavior. With that, the test passes. > > Signed-off-by: Joel Fernandes (Google) <joel@xxxxxxxxxxxxxxxxx> > --- > net/sched/sch_generic.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c > index a9aadc4e6858..63fbf640d3b2 100644 > --- a/net/sched/sch_generic.c > +++ b/net/sched/sch_generic.c > @@ -1067,7 +1067,7 @@ static void qdisc_destroy(struct Qdisc *qdisc) > > trace_qdisc_destroy(qdisc); > > - call_rcu(&qdisc->rcu, qdisc_free_cb); > + call_rcu_flush(&qdisc->rcu, qdisc_free_cb); > } I took a look at this one. qdisc_free_cb() is essentially freeing : Some per-cpu memory, and the 'struct Qdisc' I do not see why we need to force a flush for this (small ?) piece of memory.
