On Fri, Feb 16, 2024 at 10:50:10AM +0100, Benjamin Tissoires wrote:
> static bool is_rbtree_lock_required_kfunc(u32 btf_id)
> {
> return is_bpf_rbtree_api_kfunc(btf_id);
> @@ -12140,6 +12143,16 @@ static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
> }
> }
>
> + if (is_bpf_timer_set_sleepable_cb_kfunc(meta.func_id)) {
> + err = push_callback_call(env, insn, insn_idx, meta.subprogno,
> + set_timer_callback_state);
> + if (err) {
> + verbose(env, "kfunc %s#%d failed callback verification\n",
> + func_name, meta.func_id);
> + return err;
> + }
> + }
All makes sense so far.
Please squash all the fix and repost.
It's hard to do a proper review in this shape of the patch.
As far as rcu_read_lock/unlock that is done in callback...
it feels buggy and unnecessary.
bpf prog and timer won't disappear while work is queued.
array and hash map will call bpf_obj_free_timer() before going away.
And things like:
+ rcu_read_lock();
+ callback_fn = rcu_dereference(t->sleepable_cb_fn);
+ rcu_read_unlock();
+ if (!callback_fn)
+ return;
is 99% broken. if (!callback_fn) line is UAF.
