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Thu, 15 Oct 2026 18:10:00 -0700 (PDT) Content-Type: text/plain; charset=UTF-8 Date: Fri, 16 Oct 2026 01:09:59 +0000 Message-Id: Cc: "Andrii Nakryiko" , "Daniel Borkmann" , "Eduard Zingerman" , "Emil Tsalapatis" , "Ihor Solodrai" , "Tejun Heo" , , Subject: Re: [PATCH bpf-next v3 06/15] bpf: Recognize __nullable on pointer members of kernel structs From: "Alexei Starovoitov" To: "Kumar Kartikeya Dwivedi" , In-Reply-To: <20261015234125.3152346-7-memxor@gmail.com> References: <20261015234125.3152346-1-memxor@gmail.com> <20261015234125.3152346-7-memxor@gmail.com> X-Mailer: mkdraft (claude review draft; edit before sending) Content-Transfer-Encoding: 8bit Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On Fri, Oct 16, 2026 at 01:41 AM Kumar Kartikeya Dwivedi wrote: > it on, as the tag says. A tagged member of an existing struct thus asks > every program that reads it for a check, including one that reads it > through a probed pointer and relied on a NULL dereference reading as > zero. Commit log reads like BTF_TYPE_SAFE_*() can go away one day, but with this change adding __nullable to a member of task_struct breaks every tracing prog that walks through it without a check. So the tag cannot be added to existing structs and BTF_TYPE_SAFE_*_OR_NULL lists are here to stay, right?