On Thu, Sep 27, 2018 at 1:11 AM Dmitry Vyukov <dvyu...@google.com> wrote: > > Would a stack trace for call_rcu be helpful here? I have this idea for > a long time, but never get around to implementing it: > https://bugzilla.kernel.org/show_bug.cgi?id=198437
Yes. Generally speaking, showing backtrace of call_rcu() or schedule_work(0 etc. is very helpful, we are more interested in who calls call_rcu() than what that RCU callback does. BTW, yesterday I asked syzbot to test this: https://github.com/congwang/linux/commit/b7815584cf1c0bbb79e8f6fe3e4b66ba10375560 I still don't get any result. For this specific bug, we should hold a refcnt in dev->qdisc, I don't even see how call_rcu() could be invoked, unless of course we mess up with qdisc refcnt.
