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[192.26.29.3]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-499820c2897sm26637265e9.0.2026.08.12.16.15.07 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 12 Aug 2026 16:15:07 -0700 (PDT) From: Kumar Kartikeya Dwivedi To: bpf@vger.kernel.org Cc: Sashiko , Alexei Starovoitov , Andrii Nakryiko , Daniel Borkmann , Eduard Zingerman , Emil Tsalapatis , kkd@meta.com, kernel-team@meta.com Subject: [PATCH bpf-next v1] bpf: Fix func_info_aux desync after dead code elimination Date: Thu, 13 Aug 2026 01:15:05 +0200 Message-ID: <20260812231506.3558128-1-memxor@gmail.com> X-Mailer: git-send-email 2.53.0 Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=1609; i=memxor@gmail.com; h=from:subject; bh=8drCH+ILjhzZC3RjcY2l5ZIGJSzth4UYGqBU0Bz+A2c=; b=owGbwMvMwCXmrmtenRyi38x4Wi2JIavm+9Y0roefr/lf3l15+sjvn3bnY21aRb7M3t+1InVZ1 UbFBZ7zOkpZGMS4GGTFFFlK/u9jMj5R+TvQdhk3zBxWJpAhDFycAjCRo10M/z0MQmuWWZ3lY7h3 yEdsQe5qvWa3IvGeFQ8i0u4ulPVWr2FkOL3QTO+MO8PW2990V9cy19TP5jmlLX9Tj1WuOFjy1qL /jAA= X-Developer-Key: i=memxor@gmail.com; a=openpgp; fpr=B34BD741DE8494B76E2F717880EF20021D46C59B Content-Transfer-Encoding: 8bit The verifier keeps per-subprogram metadata in three parallel arrays: subprog_info, func_info, and func_info_aux. Dead code elimination can remove whole subprograms, and adjust_subprog_starts_after_remove() shifts subprog_info and func_info to close the gap, but leaves func_info_aux in place. From that point on, func_info_aux[i] no longer describes subprogram i. Shift func_info_aux together with func_info so the three arrays stay aligned after subprogram removal. Reported-by: Sashiko Link: https://lore.kernel.org/bpf/20260808064523.DE3E71F000E9@smtp.kernel.org Signed-off-by: Kumar Kartikeya Dwivedi --- kernel/bpf/fixups.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/kernel/bpf/fixups.c b/kernel/bpf/fixups.c index c4bd70befbb5..37ea85e974f1 100644 --- a/kernel/bpf/fixups.c +++ b/kernel/bpf/fixups.c @@ -401,13 +401,17 @@ static int adjust_subprog_starts_after_remove(struct bpf_verifier_env *env, sizeof(*env->subprog_info) * move); env->subprog_cnt -= j - i; - /* remove func_info */ + /* remove func_info and its aux */ if (aux->func_info) { move = aux->func_info_cnt - j; memmove(aux->func_info + i, aux->func_info + j, sizeof(*aux->func_info) * move); + if (aux->func_info_aux) + memmove(aux->func_info_aux + i, + aux->func_info_aux + j, + sizeof(*aux->func_info_aux) * move); aux->func_info_cnt -= j - i; /* func_info->insn_off is set after all code rewrites, * in adjust_btf_func() - no need to adjust -- 2.53.0