Re: [PATCH bpf-next v3 2/6] bpf: consolidate sleepable context error message printing

[Eduard Zingerman <eddyz87@gmail.com>]

On Mon, 2026-02-23 at 20:06 +0000, Mykyta Yatsenko wrote:
> Puranjay Mohan <puranjay@kernel.org> writes:
>
> > check_helper_call() prints the error message for every
> > env->cur_state->active* element when calling a sleepable helper.
> > Consolidate all of them into a single print statement.
> >
> > Signed-off-by: Puranjay Mohan <puranjay@kernel.org>
> > ---
> >  kernel/bpf/verifier.c | 40 ++++++++++++++++++----------------------
> >  1 file changed, 18 insertions(+), 22 deletions(-)
> >
> > diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
> > index c693dd663cab..c2a63f8c8984 100644
> > --- a/kernel/bpf/verifier.c
> > +++ b/kernel/bpf/verifier.c
> > @@ -11574,6 +11574,19 @@ static inline bool in_sleepable_context(struct bpf_verifier_env *env)
> >  	       in_sleepable(env);
> >  }
> >
> > +static const char *non_sleepable_context_description(struct bpf_verifier_env *env)
> > +{
> > +	if (env->cur_state->active_rcu_locks)
> > +		return "rcu_read_lock region";
> > +	if (env->cur_state->active_preempt_locks)
> > +		return "non-preemptible region";
> > +	if (env->cur_state->active_irq_id)
> > +		return "IRQ-disabled region";
> > +	if (env->cur_state->active_locks)
> > +		return "lock region";
> This check didn't exist before, did it? It looks right, but adding
> something into the commit message to explain this would be nice.
> Does it mean we can currently call a sleepable helper in the lock
> region?

This triggered me as well. Claude pointed here:

  >   The restriction is at verifier.c:20999–21007, in do_check() — before check_helper_call() is even reached:
  >   if (env->cur_state->active_locks) {
  >       if ((insn->src_reg == BPF_REG_0 &&
  >            insn->imm != BPF_FUNC_spin_unlock) ||
  >           (insn->src_reg == BPF_PSEUDO_KFUNC_CALL &&
  >            (insn->off != 0 || !kfunc_spin_allowed(insn->imm)))) {
  >           verbose(env,
  >               "function calls are not allowed while holding a lock\n");
  >           return -EINVAL;
  >       }
  >   }

Commenting about it in the commit message would be helpful 100%.

> > +	return "non-sleepable context";
> > +}
> > +

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