On Tue, 23 Apr 2024 at 17:02, Alexei Starovoitov
<alexei.starovoitov@xxxxxxxxx> wrote:
>
> On Tue, Apr 23, 2024 at 5:06 AM Kumar Kartikeya Dwivedi
> <memxor@xxxxxxxxx> wrote:
> >
> > On Tue, 23 Apr 2024 at 13:17, Jiri Olsa <olsajiri@xxxxxxxxx> wrote:
> > >
> > > On Tue, Apr 23, 2024 at 06:19:22AM +0000, Kumar Kartikeya Dwivedi wrote:
> > > > Add tests for nested cases, nested count preservation upon different
> > > > subprog calls that disable/enable preemption, and test sleepable helper
> > > > call in non-preemptible regions.
> > > >
> > > > 181/1 preempt_lock/preempt_lock_missing_1:OK
> > > > 181/2 preempt_lock/preempt_lock_missing_2:OK
> > > > 181/3 preempt_lock/preempt_lock_missing_3:OK
> > > > 181/4 preempt_lock/preempt_lock_missing_3_minus_2:OK
> > > > 181/5 preempt_lock/preempt_lock_missing_1_subprog:OK
> > > > 181/6 preempt_lock/preempt_lock_missing_2_subprog:OK
> > > > 181/7 preempt_lock/preempt_lock_missing_2_minus_1_subprog:OK
> > > > 181/8 preempt_lock/preempt_balance:OK
> > > > 181/9 preempt_lock/preempt_balance_subprog_test:OK
> > > > 181/10 preempt_lock/preempt_sleepable_helper:OK
> > >
> > > should we also check that the global function call is not allowed?
> > >
> >
> > Good point, that is missing, I'll wait for more reviews and then
> > respin with a failure test for this.
>
> I couldn't find the check in patch 1 that does:
> "Global functions are disallowed from being called".
See this part：
+ /* Only global subprogs cannot be called with preemption disabled. */
+ if (env->cur_state->active_preempt_lock) {
+ verbose(env, "global function calls are not allowed with preemption
disabled,\n"
+ "use static function instead\n");
+ return -EINVAL;
+ }
>
> And I agree that we need to allow global funcs in preempt disabled region.
> Sounds like you're planning that in the follow up.
Yeah, but it's not very simple. I noticed a few more problems with
global functions before that can be done.
They need to be marked !sleepable before do_check and only verified
with !sleepable. Otherwise if that is done later in do_check the
global function will be seen in the non-preemptible section but may
have been already verified.
We need some summarization pass for both preempt and rcu_read_lock kfuncs.
