From nobody Fri Oct 31 03:48:32 2025 Delivered-To: importer@patchew.org Received-SPF: pass (zohomail.com: domain of lists.xenproject.org designates 192.237.175.120 as permitted sender) client-ip=192.237.175.120; envelope-from=xen-devel-bounces@lists.xenproject.org; helo=lists.xenproject.org; Authentication-Results: mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of lists.xenproject.org designates 192.237.175.120 as permitted sender) smtp.mailfrom=xen-devel-bounces@lists.xenproject.org; dmarc=pass(p=quarantine dis=none) header.from=suse.com ARC-Seal: i=1; a=rsa-sha256; t=1751283791; cv=none; d=zohomail.com; s=zohoarc; b=jzJJYDzKTzac7VGXgV/uIlOavXG3vIkFRd5aF20XPbUzJyVh/M0wJszlErNSttjPDMcKL9sJX5CZJJEIPP9tMoYDVKfKYz3SU1zYeEZb+adQN9fJyFD7GRpTGj7ipHTbx3FHtXpVh3wiCbl6yZ/HqzOLB2V7/Zrtz0eG7AzQMO0= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1751283791; h=Content-Type:Content-Transfer-Encoding:Cc:Cc:Date:Date:From:From:List-Subscribe:List-Post:List-Id:List-Help:List-Unsubscribe:MIME-Version:Message-ID:Sender:Subject:Subject:To:To:Message-Id:Reply-To; bh=/eVulYssM1kQlc6S6ZkCc8s3/n4KwIjd96GCkHhSpLc=; b=lvA81QJg/z+5HnzjWwZ2vJunfw4N0oE0SZ3uIvdDb7G+WVLzLpZSReqeaO+/fEECBIN2O+vyjP2uGgpq0+URdenQ+j100S7o0YFqNxxeDpAvHCAX9OBKj2Gp70OYnSfD4+RZeCFv06y/3/DmonQXR2KmPdX2n1gkxjEK8bMKoOg= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of lists.xenproject.org designates 192.237.175.120 as permitted sender) smtp.mailfrom=xen-devel-bounces@lists.xenproject.org; dmarc=pass header.from= (p=quarantine dis=none) Return-Path: Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) by mx.zohomail.com with SMTPS id 1751283791292758.761254501382; Mon, 30 Jun 2025 04:43:11 -0700 (PDT) Received: from list by lists.xenproject.org with outflank-mailman.1029061.1402789 (Exim 4.92) (envelope-from ) id 1uWCuI-0000qc-Sm; Mon, 30 Jun 2025 11:42:42 +0000 Received: by outflank-mailman (output) from mailman id 1029061.1402789; Mon, 30 Jun 2025 11:42:42 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1uWCuI-0000qV-QC; Mon, 30 Jun 2025 11:42:42 +0000 Received: by outflank-mailman (input) for mailman id 1029061; Mon, 30 Jun 2025 11:42:41 +0000 Received: from se1-gles-flk1-in.inumbo.com ([94.247.172.50] helo=se1-gles-flk1.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1uWCuH-0000qP-Ez for xen-devel@lists.xenproject.org; Mon, 30 Jun 2025 11:42:41 +0000 Received: from mail-wr1-x42f.google.com (mail-wr1-x42f.google.com [2a00:1450:4864:20::42f]) by se1-gles-flk1.inumbo.com (Halon) with ESMTPS id 531c11b8-55a7-11f0-b894-0df219b8e170; Mon, 30 Jun 2025 13:42:39 +0200 (CEST) Received: by mail-wr1-x42f.google.com with SMTP id ffacd0b85a97d-3a588da60dfso1216770f8f.1 for ; Mon, 30 Jun 2025 04:42:39 -0700 (PDT) Received: from [10.156.60.236] (ip-037-024-206-209.um08.pools.vodafone-ip.de. [37.24.206.209]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-318c14e224csm9146641a91.32.2025.06.30.04.42.35 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 30 Jun 2025 04:42:38 -0700 (PDT) X-Outflank-Mailman: Message body and most headers restored to incoming version X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: 531c11b8-55a7-11f0-b894-0df219b8e170 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=google; t=1751283758; x=1751888558; darn=lists.xenproject.org; h=content-transfer-encoding:autocrypt:subject:from:cc:to :content-language:user-agent:mime-version:date:message-id:from:to:cc :subject:date:message-id:reply-to; bh=/eVulYssM1kQlc6S6ZkCc8s3/n4KwIjd96GCkHhSpLc=; b=cR0u/w+JYT9MAIHnQobcNIurfP42eJZGORm6I9N+m7iepJgQjLwag+zU63DSY52Chz WFqjVsR/tTH/6fBUjKZK1k94jP4w9/T2nPzP6HT8p1K2CF5Y5P+X7XSshsWgOQMkGaAQ W7VWXjtOvNfFUoU6z6RsKKRfDRsDU3AoKiAnuZBnuzokfu9KURhdE4ew6U9k2to/GZL1 7rgIgAJELYkCErqrO07erYcufqMR/8ZX34gkFnIylKi13KShGynkeiRIMnVX4H2oPPVz QYJl/wtNHGITy+wfZHWjBsSO1ocMINaqHNh88OWfk72xEY/bzH53DJ/fiPYOlDvODLYT R8GA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1751283759; x=1751888559; h=content-transfer-encoding:autocrypt:subject:from:cc:to :content-language:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=/eVulYssM1kQlc6S6ZkCc8s3/n4KwIjd96GCkHhSpLc=; b=PjfHaTNZDCLEwtilgxm+mBepwo51dcgzetbycsXA8Akk29MvJw6glCgPn3pbBRxPBG Gn2ubiRiiZSW9mGQ02honv1f3WPGIjXP4nA4fhwpkPrnN55LKroyRx0g/oSZEM0iHYdg b5JHaxZwgEK6itnwpz3Fye0kZOFEiKVpeesJ66PetblevaJEWvg5AhNVWGaqNa5N6P2m 9eDKPDU8QYhQhlQnKRxZPykvcBWc8oduITZN25HTMOJSV/hJ6r/t9rpSdelbBWJgdiU7 G3dZ3r8Ah//VEAqFfSbkYRZ7IkN8D4PSJ1yl3pOKB9QqNzYlvEw6hURnX15B406vour+ eo3Q== X-Gm-Message-State: AOJu0YxHUCx85ocuuJGuqd56tSndyhoV/enghtIplAgY3tqt/LX7FpUR yjnM1Uw3qrzEA4s04il/WjRrxkwHJ+ArwuoN66BfJf0GIRPBJY/t931BU30UtEBH9EkXyqkPXtX zEPg= X-Gm-Gg: ASbGnctykxmTSKde8MEY4WiA8PQOJym24ZOqPR8k0JZ3BpaQEoLUOh/eO1pYoW1cnuq 7KwjXeTuNDSew//zRpcAhHxzvFsU1jSh5Orbwrs8tBtf1vC6/+Bh91fv6La0fi7PslWX5xkMYnu Gp6YP54Z5XBzNN7a7DeNsd21VgTKiTcraOhhHQMvmsqmLla/Lbx5Kz591rTcA87fxXXac0a4QaP 0SSxGV9Im4AED7tRTdReEnPJrt0kRkjt7/ZA1IWtLFM4n1TpC6L/ep00lQPaLl8WHX8ibDWJhZe kHhGAXePG7hk7vh6Wumv9gi8w7SXMEurVZij85tnoo2W/j7VUDDHNq0mPFAF3Mge4CVCe6/rtzi DNkYYQRdxDb9tTzRrX5X8HnXpoJUUbM0llzPnoFpKjPwzHmM= X-Google-Smtp-Source: AGHT+IHIY/GdcoG34snCr+E2mCNV++T094l+hnLEk6ccN0U7ZVqt122MCCdAMMfs/zMDNRS1rpQ4Gg== X-Received: by 2002:a05:6000:710:b0:3aa:c9a8:a387 with SMTP id ffacd0b85a97d-3aac9a8a39cmr7320674f8f.0.1751283758561; Mon, 30 Jun 2025 04:42:38 -0700 (PDT) Message-ID: <7fa05d3f-2f85-4a42-9549-b68a486e30ea@suse.com> Date: Mon, 30 Jun 2025 13:42:31 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Content-Language: en-US To: "xen-devel@lists.xenproject.org" Cc: Andrew Cooper , =?UTF-8?Q?Roger_Pau_Monn=C3=A9?= From: Jan Beulich Subject: [PATCH] x86/SMP: guard socket_cpumask[] access in cpu_smpboot_free() Autocrypt: addr=jbeulich@suse.com; keydata= xsDiBFk3nEQRBADAEaSw6zC/EJkiwGPXbWtPxl2xCdSoeepS07jW8UgcHNurfHvUzogEq5xk hu507c3BarVjyWCJOylMNR98Yd8VqD9UfmX0Hb8/BrA+Hl6/DB/eqGptrf4BSRwcZQM32aZK 7Pj2XbGWIUrZrd70x1eAP9QE3P79Y2oLrsCgbZJfEwCgvz9JjGmQqQkRiTVzlZVCJYcyGGsD /0tbFCzD2h20ahe8rC1gbb3K3qk+LpBtvjBu1RY9drYk0NymiGbJWZgab6t1jM7sk2vuf0Py O9Hf9XBmK0uE9IgMaiCpc32XV9oASz6UJebwkX+zF2jG5I1BfnO9g7KlotcA/v5ClMjgo6Gl MDY4HxoSRu3i1cqqSDtVlt+AOVBJBACrZcnHAUSuCXBPy0jOlBhxPqRWv6ND4c9PH1xjQ3NP nxJuMBS8rnNg22uyfAgmBKNLpLgAGVRMZGaGoJObGf72s6TeIqKJo/LtggAS9qAUiuKVnygo 3wjfkS9A3DRO+SpU7JqWdsveeIQyeyEJ/8PTowmSQLakF+3fote9ybzd880fSmFuIEJldWxp Y2ggPGpiZXVsaWNoQHN1c2UuY29tPsJgBBMRAgAgBQJZN5xEAhsDBgsJCAcDAgQVAggDBBYC AwECHgECF4AACgkQoDSui/t3IH4J+wCfQ5jHdEjCRHj23O/5ttg9r9OIruwAn3103WUITZee e7Sbg12UgcQ5lv7SzsFNBFk3nEQQCACCuTjCjFOUdi5Nm244F+78kLghRcin/awv+IrTcIWF hUpSs1Y91iQQ7KItirz5uwCPlwejSJDQJLIS+QtJHaXDXeV6NI0Uef1hP20+y8qydDiVkv6l IreXjTb7DvksRgJNvCkWtYnlS3mYvQ9NzS9PhyALWbXnH6sIJd2O9lKS1Mrfq+y0IXCP10eS FFGg+Av3IQeFatkJAyju0PPthyTqxSI4lZYuJVPknzgaeuJv/2NccrPvmeDg6Coe7ZIeQ8Yj t0ARxu2xytAkkLCel1Lz1WLmwLstV30g80nkgZf/wr+/BXJW/oIvRlonUkxv+IbBM3dX2OV8 AmRv1ySWPTP7AAMFB/9PQK/VtlNUJvg8GXj9ootzrteGfVZVVT4XBJkfwBcpC/XcPzldjv+3 HYudvpdNK3lLujXeA5fLOH+Z/G9WBc5pFVSMocI71I8bT8lIAzreg0WvkWg5V2WZsUMlnDL9 mpwIGFhlbM3gfDMs7MPMu8YQRFVdUvtSpaAs8OFfGQ0ia3LGZcjA6Ik2+xcqscEJzNH+qh8V m5jjp28yZgaqTaRbg3M/+MTbMpicpZuqF4rnB0AQD12/3BNWDR6bmh+EkYSMcEIpQmBM51qM EKYTQGybRCjpnKHGOxG0rfFY1085mBDZCH5Kx0cl0HVJuQKC+dV2ZY5AqjcKwAxpE75MLFkr wkkEGBECAAkFAlk3nEQCGwwACgkQoDSui/t3IH7nnwCfcJWUDUFKdCsBH/E5d+0ZnMQi+G0A nAuWpQkjM1ASeQwSHEeAWPgskBQL Content-Transfer-Encoding: quoted-printable X-ZohoMail-DKIM: pass (identity @suse.com) X-ZM-MESSAGEID: 1751283793417116600 Content-Type: text/plain; charset="utf-8" Before CPU identification has run (and it may not have run at all e.g. when AP bringup failed altogether), cpu_data[].phys_proc_id (which is what cpu_to_socket() resolves to) can't really be used. The use of cpu_to_socket()'s result as an array index cpu_smpboot_free() therefore needs guarding, as the function will also be invoked upon AP bringup failure, in which case CPU identification may not have run. Without "x86/CPU: re-work populating of cpu_data[]" [1] the issue is less pronounced: The field starts out as zero, then has the BSP value (likely again zero) copied into it, and it is properly invalidated only in cpu_smpboot_free(). Still it is clearly wrong to use the BSP's socket number here. Making the guard work with and without the above patch applied turns out interesting: Prior to that patch, the sole invalidation done is that in cpu_smpboot_free(). Upon a later bringup attempt, the fields invalidated are overwritten by the BSP values again, though. Hence compare APIC IDs, as they cannot validly be the same once CPU identification has run. [1] https://lists.xen.org/archives/html/xen-devel/2024-02/msg00727.html Signed-off-by: Jan Beulich Acked-by: Roger Pau Monn=C3=A9 --- Sadly there was no feedback at all yet for the referenced patch. --- a/xen/arch/x86/smpboot.c +++ b/xen/arch/x86/smpboot.c @@ -958,7 +958,13 @@ static void cpu_smpboot_free(unsigned in unsigned int socket =3D cpu_to_socket(cpu); struct cpuinfo_x86 *c =3D cpu_data; =20 - if ( cpumask_empty(socket_cpumask[socket]) ) + /* + * We may come here without the CPU having run through CPU identificat= ion. + * In that case the socket number cannot be relied upon, but the respe= ctive + * socket_cpumask[] slot also wouldn't have been set. + */ + if ( c[cpu].apicid !=3D boot_cpu_data.apicid && + cpumask_empty(socket_cpumask[socket]) ) { xfree(socket_cpumask[socket]); socket_cpumask[socket] =3D NULL;