From nobody Tue Feb 10 19:16:22 2026 Received: from mail-pg1-f169.google.com (mail-pg1-f169.google.com [209.85.215.169]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 87821288530 for ; Sun, 8 Feb 2026 02:49:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.215.169 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770518984; cv=none; b=euGV0OL1pOouEhaPg/n7vSzO+oosSZVJZCLjxbl7YZnzqFCBEat+pt4qW1MxFaehAtVx+M+whT69ETWLFbkrTk4FFMfDR8liGVdwDBUfLJI58XmgCjLBIjZU8cKqe/J7U7z8W0CUitxHl8Pm1cg3Cmwft2jZfNy49IjI91Jenk8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770518984; c=relaxed/simple; bh=4TgoVZ4LlN4Q5YxWLL35dOLSFW+6qRdJJNSbmiAoSSo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=sJOM81Is67RkEU2Z7VVvVmzPVLLJu810fjbd5VvAZfuzONMMYY3IBPp95fd/hbI9zoYcsur1SvnffG4ucUx5iksUMcuem9wNFK+lhbdCBErbkh7SC/1hlXmYmS6tIFRlm184/OypDEzSl+WEl6fOwx2fgstSAGUaWK2D0+tAnxU= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=R+yrrnV1; arc=none smtp.client-ip=209.85.215.169 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="R+yrrnV1" Received: by mail-pg1-f169.google.com with SMTP id 41be03b00d2f7-c6dd5b01e14so664363a12.0 for ; Sat, 07 Feb 2026 18:49:44 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1770518984; x=1771123784; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=JEwKgEcJoSX88Rslg66p6kDbLyhXBoZdC1+Ki+lttc8=; b=R+yrrnV1x7iOqaaxD8aoxIuTYtUGP4N8hyrpnbpTiUQk4vF2MInckSAl+t97yiLZKr uijHfJqtqR4621yJUVF7dZoHHNNWaBTra9R1erjFobCGwHf72j6rsEQckRkWnnRRIUVg Npft07jXokisX79lYohws3i28jWR5+SJGR9232Q/ha+zIlc/sD3rptZzpr72uc50UfTu ucbJfkk8XxUo+fVIWJEokVZYqACMHtj/hpbvu4PQGiZ6hMM+5mJ0hWBlPQsvW1RbTDO1 +j9ru0x9UaI9cb3EcUo+BecqQpwdPMDofRgUwcOFtQSXy6LGb8K52gmlOvVmrad5TZjV u11A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1770518984; x=1771123784; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=JEwKgEcJoSX88Rslg66p6kDbLyhXBoZdC1+Ki+lttc8=; b=JNWgCPA9ya4hn6dg+AtTRFcWvNqgmHSx2ZpXtV+0DrZzep+lh+BQkmMtxr1PuEhzgc kYFF7I7q0PRmVWiUUED2Nmg/stejiVgjKS3ldHfB8vvIj+OCdR3nG7EAC2Ifbfovm+jm ugz0aKITXYvWja9xJEUKqA+j7r/hAfJwf1i1r31bVRigoshvza+wI22pajGon+qb2Xhv oa8GL2oNtLVl6ofqTfuzHAI1418jyWPC9XheJmc8guoqSUCXYL3B1aVPT3Oy+vr7YkIN +2EwbY9hEZrgLAfSfsQumK/qDLhgZpUAX/DFZ4RihnlEl2WTnwHRcnWKqVNtawzH0KQx eu9w== X-Gm-Message-State: AOJu0Yz5bisGqoX4eXGXymvMuIDvOo6W9jPsQbWKGIV3w1htP3AlupNU 73rD53n0WyyEVVrN8JTjgKSJkGkSh1lluNIDPNBwGQVYfDaLa2ZVO37N X-Gm-Gg: AZuq6aIOxZ43CU0W3tArKw5kfSj5CotU+JPgRpFJYP6cSUC46JZdnurgM5dpZKhd9ab OciIXuc0RjsgkMQuiPXp3Mz057UTPlvMSpwZeGyaaEQKWsi0cyO2+sRGm4/AngZDSb0C2pKbbhv QkZ42cEo7c05b4beW1+hMMhy5faWMksw8ALzA72VrtTEuJWNfZ7BV2RyjGDIAPfcyrdg55ZyHMJ MvOrs19i4H73Eo+kdUx406AFg7D8isSAsvpo/CUSiYRpyzxTQ7ubSmcy48QQKrZQeqpsXOENtGn 4Lv2BaXG2BpqAnzi8xlT8UQDWTB4T912X1BUuaJGRv+MQXWKZwk+t1cZyY/c+TjUwo6SB521rDc RNLN5HNubEZlWHxBjlSDvoSIdkabV8we+mOgpBXXOZN88SOUYWFIknfcklKF/LuO3OAm030XPjB fw26/ngIB9zqztguVqI4gNPqiLwbFRnQ7C2CB0mogntT00Cyom5jA= X-Received: by 2002:a17:902:ea0f:b0:2a9:450b:104 with SMTP id d9443c01a7336-2a951969dedmr65714265ad.55.1770518983811; Sat, 07 Feb 2026 18:49:43 -0800 (PST) Received: from localhost.localdomain ([113.218.252.53]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2a9521b9f5esm67194715ad.51.2026.02.07.18.49.34 (version=TLS1_3 cipher=TLS_CHACHA20_POLY1305_SHA256 bits=256/256); Sat, 07 Feb 2026 18:49:43 -0800 (PST) From: Chengkaitao To: ast@kernel.org, daniel@iogearbox.net, john.fastabend@gmail.com, andrii@kernel.org, martin.lau@linux.dev, eddyz87@gmail.com, song@kernel.org, yonghong.song@linux.dev, kpsingh@kernel.org, sdf@fomichev.me, haoluo@google.com, jolsa@kernel.org, shuah@kernel.org, yangfeng@kylinos.cn, alexei.starovoitov@gmail.com Cc: linux-kernel@vger.kernel.org, bpf@vger.kernel.org, linux-kselftest@vger.kernel.org, Kaitao Cheng Subject: [PATCH v6 4/5] bpf/verifier: allow using bpf_kptr_xchg even if the MEM_RCU flag is set Date: Sun, 8 Feb 2026 10:48:45 +0800 Message-ID: <20260208024846.18653-5-pilgrimtao@gmail.com> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20260208024846.18653-1-pilgrimtao@gmail.com> References: <20260208024846.18653-1-pilgrimtao@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Kaitao Cheng For the following scenario: struct tree_node { struct bpf_refcount ref; struct bpf_rb_node node; struct node_data __kptr * node_data; u64 key; }; This means node_data would have the type PTR_TO_BTF_ID | MEM_ALLOC | NON_OWN_REF | MEM_RCU. When traversing an rbtree using bpf_rbtree_left/right, if we need to use bpf_kptr_xchg to read the __kptr pointer, we still need to follow the remove-read-add sequence. This patch allows us to use bpf_kptr_xchg to directly read the __kptr pointer without any prior operations. Signed-off-by: Kaitao Cheng Signed-off-by: Feng Yang --- kernel/bpf/verifier.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index bb3ff4bbb3a2..50cb4956e5bb 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -9261,7 +9261,8 @@ static const struct bpf_reg_types kptr_xchg_dest_type= s =3D { .types =3D { PTR_TO_MAP_VALUE, PTR_TO_BTF_ID | MEM_ALLOC, - PTR_TO_BTF_ID | MEM_ALLOC | NON_OWN_REF + PTR_TO_BTF_ID | MEM_ALLOC | NON_OWN_REF, + PTR_TO_BTF_ID | MEM_ALLOC | NON_OWN_REF | MEM_RCU } }; static const struct bpf_reg_types dynptr_types =3D { @@ -9422,6 +9423,7 @@ static int check_reg_type(struct bpf_verifier_env *en= v, u32 regno, case PTR_TO_BTF_ID | MEM_ALLOC: case PTR_TO_BTF_ID | MEM_PERCPU | MEM_ALLOC: case PTR_TO_BTF_ID | MEM_ALLOC | NON_OWN_REF: + case PTR_TO_BTF_ID | MEM_ALLOC | NON_OWN_REF | MEM_RCU: if (meta->func_id !=3D BPF_FUNC_spin_lock && meta->func_id !=3D BPF_FUNC= _spin_unlock && meta->func_id !=3D BPF_FUNC_kptr_xchg) { verifier_bug(env, "unimplemented handling of MEM_ALLOC"); --=20 2.50.1 (Apple Git-155)