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Thu, 18 Sep 2025 15:02:21 -0700 (PDT) Received: from [192.168.28.36] ([38.34.87.7]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-269802df852sm35580005ad.87.2025.09.18.15.02.20 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 18 Sep 2025 15:02:21 -0700 (PDT) Message-ID: Subject: Re: [PATCH bpf-next v3 1/2] bpf: Enforce RCU protection for KF_RCU_PROTECTED From: Eduard Zingerman To: Kumar Kartikeya Dwivedi Cc: bpf@vger.kernel.org, Andrea Righi , Alexei Starovoitov , Andrii Nakryiko , Daniel Borkmann , Martin KaFai Lau , Tejun Heo , kkd@meta.com, kernel-team@meta.com Date: Thu, 18 Sep 2025 15:02:18 -0700 In-Reply-To: References: <20250917032755.4068726-1-memxor@gmail.com> <20250917032755.4068726-2-memxor@gmail.com> <412f49fa12de7c7f5d0461b56fd4e0b6882fa0ad.camel@gmail.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.56.2 (3.56.2-1.fc42) Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On Thu, 2025-09-18 at 23:59 +0200, Kumar Kartikeya Dwivedi wrote: [...] > > The change I suggest does not invalidate this mechanics. > > The iterator is still marked with MEM_RCU and this mark is converted > > to PTR_UNTRUSTED when RCU section exits. > > The check for PTR_UNTRUSTED happens in process_iter_arg() called > > from check_kfunc_args(). >=20 > Oh, I see. You mean is_iter_valid_reg_init etc. will complain on > seeing that PTR_UNTRUSTED? > Hmm, I guess that might work. I can respin or do it as a follow up, > whatever works best. Thank you, followup works for me. [...]