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([2620:10d:c090:500::1f1f]) by smtp.gmail.com with ESMTPSA id 5a478bee46e88-2bd7dc167b2sm7150309eec.28.2026.02.24.10.17.46 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 24 Feb 2026 10:17:46 -0800 (PST) Message-ID: <20ec0bf67e3664eeac349dde21bdda2d3546079b.camel@gmail.com> Subject: Re: [PATCH bpf-next v3 3/6] bpf: Add KF_FORBID_SLEEP modifier for KF_ACQUIRE kfuncs From: Eduard Zingerman To: Puranjay Mohan Cc: bpf@vger.kernel.org, Alexei Starovoitov , Andrii Nakryiko , Daniel Borkmann , Martin KaFai Lau , Kumar Kartikeya Dwivedi , Mykyta Yatsenko , kernel-team@meta.com Date: Tue, 24 Feb 2026 10:17:45 -0800 In-Reply-To: References: <20260223174659.2749964-1-puranjay@kernel.org> <20260223174659.2749964-4-puranjay@kernel.org> <562fc6aeef17412ba8965bc4938fe9c0dbbe0f9e.camel@gmail.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.58.2 (3.58.2-1.fc43) Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On Tue, 2026-02-24 at 15:24 +0000, Puranjay Mohan wrote: [...] > > - remove the following check from do_check_insn(): > >=20 > > > if (env->cur_state->active_locks) { > > > if ((insn->src_reg =3D=3D BPF_REG_0 && > > > insn->imm !=3D BPF_FUNC_spin_unlock) || > > > (insn->src_reg =3D=3D BPF_PSEUDO_KFUNC_CALL && > > > (insn->off !=3D 0 || !kfunc_spin_allowed(insn->imm)))) { > > > verbose(env, > > > "function calls are not allowed while holding a lock\= n"); > > > return -EINVAL; > > > } > > > } > >=20 > > Relying instead on `sleepable && !in_sleepable_context()` checks in > > check_kfunc_call() and check_helper_call(). (As one more refactoring = patch). >=20 > But removing the above hunk has other effects, this check is not just > about sleepable but all function calls under bpf_spin_lock. Do we want > to relax this now? Discussed this off-list. The side-effect of this change is that calls to any non-sleepable helpers / kfuncs would be allowed while holding a spin lock. This should be fine, but probably belongs to a separate series.