On 25/08/25 04:29PM, Eduard Zingerman wrote:
> On Sat, 2025-08-16 at 18:06 +0000, Anton Protopopov wrote:
>
> [...]
>
> > diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
> > index 5d1650af899d..27e9c30ad6dc 100644
> > --- a/kernel/bpf/core.c
> > +++ b/kernel/bpf/core.c
>
> [...]
>
> > @@ -1544,6 +1562,7 @@ struct bpf_prog *bpf_jit_blind_constants(struct bpf_prog *prog)
> > }
> >
> > clone->blinded = 1;
> > + clone->len = insn_cnt;
>
> Is this an old bug? Does it require a separate commit and a fixes tag?
Turns out this change is actually not needed, as the
bpf_patch_insn_single() function sets the len properly.
> > return clone;
> > }
> > #endif /* CONFIG_BPF_JIT */
> > diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
> > index e1f7744e132b..863b7114866b 100644
> > --- a/kernel/bpf/verifier.c
> > +++ b/kernel/bpf/verifier.c
>
> [...]
>
> > @@ -21665,7 +21666,15 @@ static int jit_subprogs(struct bpf_verifier_env *env)
> > func[i]->aux->might_sleep = env->subprog_info[i].might_sleep;
> > if (!i)
> > func[i]->aux->exception_boundary = env->seen_exception;
> > +
> > + /*
> > + * To properly pass the absolute subprog start to jit
> > + * all instruction adjustments should be accumulated
> > + */
> > + instructions_added -= func[i]->len;
> > func[i] = bpf_int_jit_compile(func[i]);
> > + instructions_added += func[i]->len;
> > +
>
> Nit: This -= / += pair is a bit hackish, maybe add a separate variable
> to compute current delta?
Sure, I've rewrote this piece.
> > if (!func[i]->jited) {
> > err = -ENOTSUPP;
> > goto out_free;
