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([2620:10d:c090:500::2:8a9]) by smtp.gmail.com with ESMTPSA id 5a478bee46e88-30296dcb6f6sm956046eec.17.2026.05.13.15.55.31 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 13 May 2026 15:55:33 -0700 (PDT) Message-ID: <66355df814a639c463b5f51e96fd539aa30f0679.camel@gmail.com> Subject: Re: [PATCH RESEND bpf-next v10 7/8] bpf: allow non-owning list-node args via __nonown_allowed From: Eduard Zingerman To: Kaitao cheng , ast@kernel.org, corbet@lwn.net, martin.lau@linux.dev, daniel@iogearbox.net, andrii@kernel.org, song@kernel.org, yonghong.song@linux.dev, john.fastabend@gmail.com, kpsingh@kernel.org, sdf@fomichev.me, haoluo@google.com, jolsa@kernel.org, shuah@kernel.org, chengkaitao@kylinos.cn, skhan@linuxfoundation.org, memxor@gmail.com Cc: bpf@vger.kernel.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, vmalik@redhat.com, linux-kselftest@vger.kernel.org Date: Wed, 13 May 2026 15:55:31 -0700 In-Reply-To: <0419643c9a04bf0824066742e52e3f197b43909b.camel@gmail.com> References: <20260512055919.95716-1-kaitao.cheng@linux.dev> <20260512055919.95716-8-kaitao.cheng@linux.dev> <0419643c9a04bf0824066742e52e3f197b43909b.camel@gmail.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.58.3 (3.58.3-1.fc43) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On Wed, 2026-05-13 at 15:37 -0700, Eduard Zingerman wrote: > On Tue, 2026-05-12 at 13:59 +0800, Kaitao cheng wrote: > > From: Kaitao Cheng > >=20 > > KF_ARG_PTR_TO_LIST_NODE normally requires an owning reference > > (PTR_TO_BTF_ID | MEM_ALLOC with ref_obj_id). Introduce and use > > the __nonown_allowed annotation on selected list-node arguments > > so non-owning references with ref_obj_id=3D=3D0 are accepted as well. > >=20 > > This enables passing bpf_list_front() / bpf_list_back() results to: > >=20 > > bpf_list_add() as insertion point (prev) > > bpf_list_del() as deletion target (node) > > bpf_list_is_first/last() as query target (node) > >=20 > > Verifier keeps existing owning-ref checks by default; only arguments > > annotated with __nonown_allowed bypass MEM_ALLOC/ref_obj_id checks > > and then follow the same list-node validation path. > >=20 > > Signed-off-by: Kaitao Cheng > > --- Also, I think it is worthwhile to move this patch before the patches that introduce kfuncs that use the __nonown_allowed annotation. (In case if this series goes to v11).