On Mon, Nov 07, 2022 at 09:15:26AM IST, Alexei Starovoitov wrote: > On Sun, Nov 6, 2022 at 6:34 PM Alexei Starovoitov > <alexei.starovoitov@xxxxxxxxx> wrote: > > > > > > > > For bpf_timer, it would mean moving drop_prog_refcnt outside spin lock critical > > > section. hrtimer_cancel is already done after the unlock. For bpf_list_head, it > > > > would mean swapping out the list_head and then draining it outside the lock. > > > > That also works. > > drop_prog_refcnt() can be moved after unlock. > > Don't see any race. > > I mean not the whole function obviously. > Instead of > static void drop_prog_refcnt(struct bpf_hrtimer *t) > it can become > static struct bpf_prog *drop_prog_refcnt(struct bpf_hrtimer *t) > t->prog and callback_fn should only be manipulated > under lock. > bpf_prog_put itself can happen after unlock. Right, both t->prog and t->callback_fn need to be set to NULL under the lock. I will send out the bpf_timer change separately. For now, I moved list draining out of the lock in my series and removed the check on BPF_PROG_TYPE_TRACING, and posted it.
