Re: [PATCH net 5/5] net: restrict message_cost and message_burst to non-negative values

[Jiayuan Chen]

On 10/23/26 8:55 PM, Fernando Fernandez Mancera wrote:
[...]
> > >   #ifdef CONFIG_BPF_JIT
> > >   static int proc_dointvec_minmax_bpf_enable(const struct ctl_table 
> > > *table, int write,
> > >                          void *buffer, size_t *lenp,
> > > @@ -544,14 +560,15 @@ static struct ctl_table net_core_table[] = {
> > >           .data        = &net_ratelimit_state.interval,
> > >           .maxlen        = sizeof(int),
> > >           .mode        = 0644,
> > > -        .proc_handler    = proc_dointvec_jiffies,
> > > +        .proc_handler    = proc_do_message_cost,
> > >       },
> > >       {
> > >           .procname    = "message_burst",
> > >           .data        = &net_ratelimit_state.burst,
> > >           .maxlen        = sizeof(int),
> > >           .mode        = 0644,
> > > -        .proc_handler    = proc_dointvec,
> > > +        .proc_handler    = proc_dointvec_minmax,
> > > +        .extra1        = SYSCTL_ZERO,
> > >       },
> > >   #ifdef CONFIG_RPS
> > >       {
> > > --
> > > 2.43.0
> >
> > I would prefer something like this [1] (not tested and not compiled).
> > This is more in line with the patterns inside the jiffies.c file. I put
> > SYSCTL_ZERO there, but I have a doubt if you actually need SYSCTL_ONE.

Thanks Joel and Fernando, good to hear this.

I actually had almost the same proc_dointvec_jiffies_minmax() locally at 
first,

but then thought "this touches sysctl core, better not" and went with 
the local handler
instead.

Glad I was wrong about that :)


> > If the interval variable can be zero, then leave it as SYSCTL_ZERO, but
> > if it cant be zero and can be one the use SYSCTL_ONE
>
> FWIW, I also like this solution and indeed we can convert other users 
> in the future.
>
> About SYSCTL_ZERO, I believe it is the right choice. AFAIU, it just 
> disables limiting.

Agreed on SYSCTL_ZERO. interval == 0 is the documented "never limit"
case in ___ratelimit(), so it has to stay allowed.


> Thanks,
> Fernando.