From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f180.google.com (mail-pl1-f180.google.com [209.85.214.180]) (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 5B08F2DFA31 for ; Mon, 2 Feb 2026 05:58:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.180 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770011921; cv=none; b=ZngYNaQfX1O/lOS1eqHpnYzGy2ncA+s11uEmp/MJMAcpKBAYWnqg6Prmnfj1/uqu8TxOwbDiVTc9tTS/YEHVECBIgCzXgLKh6vB8WdhajQw97k5QwLtCrbqHvDZpQYoU3oObLpDVF6kGSfoOJwZ0K0UAalmair4K/Hdclm5HFjc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770011921; c=relaxed/simple; bh=uUL3+hIqzzN4FF56+RZlxBho1NEz93n03uZmaBVx188=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=TlCEMmqvnozymNGmj360uYTySLR8NfbkdkyeTg0KvI6gqjtzzYov4jSKoUj4UOMXmXWE41vk1VjxNv7qp7IKQI59HrD4Zizuw8LebyLXlmM5plb8g/op6RczBqoLFzArti2HKsRheZpBVIJgTmZQTwR71NqKTHgxiD3Pb7iH7Ls= 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=Zfyqaqaz; arc=none smtp.client-ip=209.85.214.180 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="Zfyqaqaz" Received: by mail-pl1-f180.google.com with SMTP id d9443c01a7336-2a0c09bb78cso33547525ad.0 for ; Sun, 01 Feb 2026 21:58:40 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1770011920; x=1770616720; 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=32rXQW4BVZZQ4FbVA0RQJRaOaveBTs70Lc0Lq+KuBq8=; b=Zfyqaqaz4Mx2MA20CZsGw4ppd1SZgf4inyGhFsQKWnbn2i1y0AHD7oeB8+F0PaBVCu UZb99d0Xy4wCCcd1Iqu6ro4lJnQwEk0p3O89TrjSsDvQYeG8TYIj9AqYO+Z5NCv4WWU1 5B9qTUNfKkGELUm3ZDfAOS2ml4eMTX1HXXcgBQ+q7mV4vTx0OXRp/gX6REPGDYLhkOcX 9Sdn+vaIxi4prkZoH2roAueM8bI1nwldYwfmT2ab3M7QBl28o596dz52bt8F/CLK2A5r Q66OTJtPHyPMnkzrEXo4SeQsbJf55o+sg1hg35uOmMiojavebauwGLS8ETDRWrsiWOlR 9MdA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1770011920; x=1770616720; 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=32rXQW4BVZZQ4FbVA0RQJRaOaveBTs70Lc0Lq+KuBq8=; b=fkHqiXRKOeWJ2vt57hyNZYmRer3Em+keFz1EqnOs7jWCQAAD0LTdbbHD4eBrOEcBux yRVlaGkiKwK+My9GGmgQSylwC74vrxjgbbKrSC8sU87pLqkLWXeuNr9EK63b6YV+hFV0 WKMI8j5inS8IkAPLEUpZK2iGBQU+H159ej+FD4j3WR+/BHh4uHg7ES8tT5wpAv3lHCV0 E8/mz6wS1tHXH5fAAp2FGMQsuzjAjQSCZS2La2YYof5pTY35y8NLjOT3bntXFFWOtOoJ flp2w121tPhFTXggTTTzq/RmcSY3vBLb00OY5mwh5V3USYHyFgOVDbi9Ku/+Xc2nTeZp Jgfg== X-Forwarded-Encrypted: i=1; AJvYcCWb6zLppZMSVnNFznsP1Ox3zdyYwvqd1aZEgeMOsG+qDPGpoNYzBToCSw7Mnvt/BCSDrko=@vger.kernel.org X-Gm-Message-State: AOJu0Yw0KiNwgvsjKw8lggpPC59wSsZVht5pScrk5pMAmPyzZh6GZ9YM fvO2f2HBb6/bft9Qj5jJP993wFDBiA3Dl/b4xFqQ+takchJyn1njZVfe X-Gm-Gg: AZuq6aKh6LBfPGoQpzfU2uqxE6AjO8MGn+CIiS6brWw2IzmvGdaMImPeMWAaJuOL+kQ s78CJJ8dS9hoUJ/KIME6Ws7KY8cbv2sGZHJuQwgYJFzGR9oxDCtS/HhlDFjRu9GNS/EUKTw0L/l sWZP8A8XAp0MeotSxDwOaFb2bbCCNPX8GCGiuAgT1wYiqden0auqyoLF8bawQ3krEqUWl8rYvgS FLCjkrVAeXPt/YjFjUHLl/2odWAtcMEbMMuB4OOMaDMwUq4VylaLMqLaTV+Voze+k/uLVV3527t Yq7C2d3+XYqaF23AKn1YvWUz75D3U1/v7jkI01XA70n1355aFubyRoc9RzUrhjSjbSHrQqKTdDE IS3MrJdA8TCLrBHpNYvnnbDkV+4ACLhMf2FUrT81+cp4T9DNG2u98Hw9oDUIeIbLC9QFoKSOV1K cPejg3Evx33ACDSHvGU7cguWCbkjXNMvoxejNHCRoPHA== X-Received: by 2002:a17:902:e749:b0:2a7:5f26:aaf9 with SMTP id d9443c01a7336-2a8bd4c6f2cmr147962965ad.14.1770011919560; Sun, 01 Feb 2026 21:58:39 -0800 (PST) Received: from localhost.localdomain ([116.128.244.171]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2a88b4173a2sm139121185ad.30.2026.02.01.21.58.32 (version=TLS1_3 cipher=TLS_CHACHA20_POLY1305_SHA256 bits=256/256); Sun, 01 Feb 2026 21:58:39 -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, Chengkaitao Subject: [PATCH RESEND v3 1/3] bpf/verifier: allow calling bpf_kptr_xchg while holding a lock Date: Mon, 2 Feb 2026 13:58:16 +0800 Message-ID: <20260202055818.78231-2-pilgrimtao@gmail.com> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20260202055818.78231-1-pilgrimtao@gmail.com> References: <20260202055818.78231-1-pilgrimtao@gmail.com> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Chengkaitao For the following scenario: struct tree_node { struct bpf_rb_node node; struct request __kptr *req; u64 key; }; struct bpf_rb_root tree_root __contains(tree_node, node); struct bpf_spin_lock tree_lock; If we need to traverse all nodes in the rbtree, retrieve the __kptr pointer from each node, and read kernel data from the referenced object, using bpf_kptr_xchg appears unavoidable. This patch skips the BPF verifier checks for bpf_kptr_xchg when called while holding a lock. Signed-off-by: Chengkaitao --- kernel/bpf/verifier.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 3135643d5695..05a6a6606b6c 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -20387,7 +20387,8 @@ static int do_check_insn(struct bpf_verifier_env *env, bool *do_print_state) if (env->cur_state->active_locks) { if ((insn->src_reg == BPF_REG_0 && - insn->imm != BPF_FUNC_spin_unlock) || + insn->imm != BPF_FUNC_spin_unlock && + insn->imm != BPF_FUNC_kptr_xchg) || (insn->src_reg == BPF_PSEUDO_KFUNC_CALL && (insn->off != 0 || !kfunc_spin_allowed(insn->imm)))) { verbose(env, -- 2.50.1 (Apple Git-155)