Re: [PATCH v1 bpf-next 03/11] bpf, x86: add new map type: instructions array

[Anton Protopopov <a.s.protopopov@gmail.com>]

On 25/08/25 02:05PM, Eduard Zingerman wrote:
> On Sat, 2025-08-16 at 18:06 +0000, Anton Protopopov wrote:
> 
> [...]
> 
> > --- /dev/null
> > +++ b/kernel/bpf/bpf_insn_array.c
> 
> [...]
> 
> > +int bpf_insn_array_ready(struct bpf_map *map)
> > +{
> > +	struct bpf_insn_array *insn_array = cast_insn_array(map);
> > +	guard(mutex)(&insn_array->state_mutex);
> > +	int i;
> > +
> > +	for (i = 0; i < map->max_entries; i++) {
> > +		if (insn_array->ptrs[i].user_value.xlated_off == INSN_DELETED)
> > +			continue;
> > +		if (!insn_array->ips[i]) {
> > +			/*
> > +			 * Set the map free on failure; the program owning it
> > +			 * might be re-loaded with different log level
> > +			 */
> > +			insn_array->state = INSN_ARRAY_STATE_FREE;
> > +			return -EFAULT;
> 
> This shouldn't happen, right?
> If so, maybe use verifier_bug here with some description?
> (and move bpf_insn_array_ready() call to verifier.c:bpf_check(),
>  so that the log pointer is available).

Shouldn't happen. But, unfortunately, only after
bpf_prog_select_runtime() which is executed after bpf_check(). Might
be nice to allow jit/bpf_prog_select_runtime to use the verifier
environment.

(Not 100% similar, but related to blinding part of this series:
blinding is happening as the very first step of every jit (initially
was implemented for x86, and then copy/pasted to everywhere else).
Might be nice to move it to be one of the last stages of verifier,
then code is shared and env is available as well. For this series I
had to add a bit of custom code to support instruction arrays at this
blinding stage.)

> > +		}
> > +	}
> > +
> > +	insn_array->state = INSN_ARRAY_STATE_READY;
> > +	return 0;
> > +}
> 
> [...]