From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 28412C61DB6 for ; Tue, 25 Aug 2026 09:38:04 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 3F2CF6B008A; Tue, 25 Aug 2026 05:38:03 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 3A4426B008C; Tue, 25 Aug 2026 05:38:03 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 292AC6B009D; Tue, 25 Aug 2026 05:38:03 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id EEC166B008A for ; Tue, 25 Aug 2026 05:38:02 -0400 (EDT) Received: from smtpin08.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay05.hostedemail.com (Postfix) with ESMTP id 0C59B40171 for ; Tue, 25 Aug 2026 09:38:02 +0000 (UTC) X-FDA: 85139290404.08.B64DB7B Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by imf29.hostedemail.com (Postfix) with ESMTP id 55439120006 for ; Tue, 25 Aug 2026 09:38:00 +0000 (UTC) Authentication-Results: imf29.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=XjGu6Cl7; spf=pass (imf29.hostedemail.com: domain of jirislaby@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=jirislaby@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1787650680; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=uHMbwppkoGY2sHxRgCTh9Ue6zxQIMWpcljbfz+/NqZQ=; b=0ZRjSMpEmPgDfqTw+9IKo1JXX0UGZP7q++cU/s1qttd1hS+TgyVaKaR5bSkMM/A3MidwMv tsCLgVNyCetd56Kawgw7LKpcFxN00ZedCs0ams/ViqaqxJAQ+nTDRhDmH4wJWhmvSL+cdn gaHVM7kOBjIAZMLppntQr9gPy9/tcIc= ARC-Authentication-Results: i=1; imf29.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=XjGu6Cl7; spf=pass (imf29.hostedemail.com: domain of jirislaby@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=jirislaby@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1787650680; b=gFru2sZTtGjIZp1o1ZcWhz7WZdrNf5VcoLvdwAHVkCc/LqSw19Bnyg+MlGtRvNeaWy6TpF yNGayepUfX/UfNqU7AW3ERoF+p7wNTbwvRYxW/GnyZomX3rXa4wvoVwoNsdcq1PbVJoc61 D5ZBeFCwkdhjZp39e/uwoTINkdROP7w= Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id CC8A0601E0; Tue, 25 Aug 2026 09:37:59 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2D2391F000E9; Tue, 25 Aug 2026 09:37:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1787650679; bh=uHMbwppkoGY2sHxRgCTh9Ue6zxQIMWpcljbfz+/NqZQ=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=XjGu6Cl72Sv4ZQ8ciSrINAMtN6nEKV9RpdGUJHvBp+azwFwyeB1z73CkMeIrUmeoJ LWn0l23yBBk6KjDAZIqAc4NB3RL272gxTQzY5cBfv0B4Gbi0WzKeLX0TFUuXcA7tiU SqrXzLtr2+8QqlAcSiF0adrEUoRlUDQJMglWQSgSynVLwwovlJr5oYCdEzIWgFlHYQ m4nyxFRlpOTfwNHd7jwcSeMtzTLJ8Z5vBici7PAS8FF11OI+Q5XqWRYN9JGaX5UGTb BqUGY9LP/kyTJXYVFFY+WwZyp5CgpteabzL7IL1+EzknQkS9T3+XTIsVZnjSH/0h6M hIioTqJLOg76g== Message-ID: <0a00c5c4-5dca-4957-b4cf-2a52efb2deb1@kernel.org> Date: Tue, 25 Aug 2026 11:37:50 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 3/5] x86/alternative: exclude text poking against change_page_attr() To: Mike Rapoport , Dave Hansen Cc: Andrew Morton , Andy Lutomirski , Borislav Petkov , David CARLIER , David Hildenbrand , Ingo Molnar , Jason Gunthorpe , Juergen Gross , Kevin Tian , Kiryl Shutsemau , "Liam R. Howlett" , Lorenzo Stoakes , Lu Baolu , Nikunj A Dadhania , Pedro Falcato , "H. Peter Anvin" , Peter Zijlstra , Shakeel Butt , Steffen Dirkwinkel , Suren Baghdasaryan , Thomas Gleixner , Toshi Kani , Vishal Moola , Vlastimil Babka , Will Deacon , iommu@lists.linux.dev, linux-kernel@vger.kernel.org, linux-mm@kvack.org, stable@vger.kernel.org, syzbot@syzkaller.appspotmail.com, x86@kernel.org References: <20260813-cpa-fixes-v2-0-39b4ff90f91d@kernel.org> <20260813-cpa-fixes-v2-3-39b4ff90f91d@kernel.org> Content-Language: en-US From: Jiri Slaby Autocrypt: addr=jirislaby@kernel.org; keydata= xsFNBE6S54YBEACzzjLwDUbU5elY4GTg/NdotjA0jyyJtYI86wdKraekbNE0bC4zV+ryvH4j rrcDwGs6tFVrAHvdHeIdI07s1iIx5R/ndcHwt4fvI8CL5PzPmn5J+h0WERR5rFprRh6axhOk rSD5CwQl19fm4AJCS6A9GJtOoiLpWn2/IbogPc71jQVrupZYYx51rAaHZ0D2KYK/uhfc6neJ i0WqPlbtIlIrpvWxckucNu6ZwXjFY0f3qIRg3Vqh5QxPkojGsq9tXVFVLEkSVz6FoqCHrUTx wr+aw6qqQVgvT/McQtsI0S66uIkQjzPUrgAEtWUv76rM4ekqL9stHyvTGw0Fjsualwb0Gwdx ReTZzMgheAyoy/umIOKrSEpWouVoBt5FFSZUyjuDdlPPYyPav+hpI6ggmCTld3u2hyiHji2H cDpcLM2LMhlHBipu80s9anNeZhCANDhbC5E+NZmuwgzHBcan8WC7xsPXPaiZSIm7TKaVoOcL 9tE5aN3jQmIlrT7ZUX52Ff/hSdx/JKDP3YMNtt4B0cH6ejIjtqTd+Ge8sSttsnNM0CQUkXps w98jwz+Lxw/bKMr3NSnnFpUZaxwji3BC9vYyxKMAwNelBCHEgS/OAa3EJoTfuYOK6wT6nadm YqYjwYbZE5V/SwzMbpWu7Jwlvuwyfo5mh7w5iMfnZE+vHFwp/wARAQABzSFKaXJpIFNsYWJ5 IDxqaXJpc2xhYnlAa2VybmVsLm9yZz7CwXcEEwEIACEFAlW3RUwCGwMFCwkIBwIGFQgJCgsC BBYCAwECHgECF4AACgkQvSWxBAa0cEnVTg//TQpdIAr8Tn0VAeUjdVIH9XCFw+cPSU+zMSCH eCZoA/N6gitEcnvHoFVVM7b3hK2HgoFUNbmYC0RdcSc80pOF5gCnACSP9XWHGWzeKCARRcQR 4s5YD8I4VV5hqXcKo2DFAtIOVbHDW+0okOzcecdasCakUTr7s2fXz97uuoc2gIBB7bmHUGAH XQXHvdnCLjDjR+eJN+zrtbqZKYSfj89s/ZHn5Slug6w8qOPT1sVNGG+eWPlc5s7XYhT9z66E l5C0rG35JE4PhC+tl7BaE5IwjJlBMHf/cMJxNHAYoQ1hWQCKOfMDQ6bsEr++kGUCbHkrEFwD UVA72iLnnnlZCMevwE4hc0zVhseWhPc/KMYObU1sDGqaCesRLkE3tiE7X2cikmj/qH0CoMWe gjnwnQ2qVJcaPSzJ4QITvchEQ+tbuVAyvn9H+9MkdT7b7b2OaqYsUP8rn/2k1Td5zknUz7iF oJ0Z9wPTl6tDfF8phaMIPISYrhceVOIoL+rWfaikhBulZTIT5ihieY9nQOw6vhOfWkYvv0Dl o4GRnb2ybPQpfEs7WtetOsUgiUbfljTgILFw3CsPW8JESOGQc0Pv8ieznIighqPPFz9g+zSu Ss/rpcsqag5n9rQp/H3WW5zKUpeYcKGaPDp/vSUovMcjp8USIhzBBrmI7UWAtuedG9prjqfO wU0ETpLnhgEQAM+cDWLL+Wvc9cLhA2OXZ/gMmu7NbYKjfth1UyOuBd5emIO+d4RfFM02XFTI t4MxwhAryhsKQQcA4iQNldkbyeviYrPKWjLTjRXT5cD2lpWzr+Jx7mX7InV5JOz1Qq+P+nJW YIBjUKhI03ux89p58CYil24Zpyn2F5cX7U+inY8lJIBwLPBnc9Z0An/DVnUOD+0wIcYVnZAK DiIXODkGqTg3fhZwbbi+KAhtHPFM2fGw2VTUf62IHzV+eBSnamzPOBc1XsJYKRo3FHNeLuS8 f4wUe7bWb9O66PPFK/RkeqNX6akkFBf9VfrZ1rTEKAyJ2uqf1EI1olYnENk4+00IBa+BavGQ 8UW9dGW3nbPrfuOV5UUvbnsSQwj67pSdrBQqilr5N/5H9z7VCDQ0dhuJNtvDSlTf2iUFBqgk 3smln31PUYiVPrMP0V4ja0i9qtO/TB01rTfTyXTRtqz53qO5dGsYiliJO5aUmh8swVpotgK4 /57h3zGsaXO9PGgnnAdqeKVITaFTLY1ISg+Ptb4KoliiOjrBMmQUSJVtkUXMrCMCeuPDGHo7 39Xc75lcHlGuM3yEB//htKjyprbLeLf1y4xPyTeeF5zg/0ztRZNKZicgEmxyUNBHHnBKHQxz 1j+mzH0HjZZtXjGu2KLJ18G07q0fpz2ZPk2D53Ww39VNI/J9ABEBAAHCwV8EGAECAAkFAk6S 54YCGwwACgkQvSWxBAa0cEk3tRAAgO+DFpbyIa4RlnfpcW17AfnpZi9VR5+zr496n2jH/1ld wRO/S+QNSA8qdABqMb9WI4BNaoANgcg0AS429Mq0taaWKkAjkkGAT7mD1Q5PiLr06Y/+Kzdr 90eUVneqM2TUQQbK+Kh7JwmGVrRGNqQrDk+gRNvKnGwFNeTkTKtJ0P8jYd7P1gZb9Fwj9YLx jhn/sVIhNmEBLBoI7PL+9fbILqJPHgAwW35rpnq4f/EYTykbk1sa13Tav6btJ+4QOgbcezWI wZ5w/JVfEJW9JXp3BFAVzRQ5nVrrLDAJZ8Y5ioWcm99JtSIIxXxt9FJaGc1Bgsi5K/+dyTKL wLMJgiBzbVx8G+fCJJ9YtlNOPWhbKPlrQ8+AY52Aagi9WNhe6XfJdh5g6ptiOILm330mkR4g W6nEgZVyIyTq3ekOuruftWL99qpP5zi+eNrMmLRQx9iecDNgFr342R9bTDlb1TLuRb+/tJ98 f/bIWIr0cqQmqQ33FgRhrG1+Xml6UXyJ2jExmlO8JljuOGeXYh6ZkIEyzqzffzBLXZCujlYQ DFXpyMNVJ2ZwPmX2mWEoYuaBU0JN7wM+/zWgOf2zRwhEuD3A2cO2PxoiIfyUEfB9SSmffaK/ S4xXoB6wvGENZ85Hg37C7WDNdaAt6Xh2uQIly5grkgvWppkNy4ZHxE+jeNsU7tg= In-Reply-To: <20260813-cpa-fixes-v2-3-39b4ff90f91d@kernel.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Stat-Signature: trmwrzakgwbr96azc4uz3boyc394ooy5 X-Rspamd-Queue-Id: 55439120006 X-Rspam-User: X-Rspamd-Server: rspam12 X-HE-Tag: 1787650680-47112 X-HE-Meta: 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 EMBxNlb2 37O8D4SG5i9ssS9wN819h1dPVeUWHwQIiuDKmj551CPa66B7FMaeXLyzPICy8kd4j1GsXvNBqYMerLAx/l+cxgRul38RS26Ly5QTxVQefSieOI9fHFKlxRYelTBnan6koUiTF0JB+tISQQ0AyT0nc+2/M6LTU4KPIi69l+nCqCm0cc+0eeL790gvEySgMJI30zMHFnmXIzWPvtJg9cFZa/QxKNzT/qVhZgIp9pI08OhUg2goakYHZhcMlvPnDwXBukKCH3RdrAb1AVa3yDjfbUdMkuvjX3fhLpq2lQRN0vCEseleXbZxKIvnYGKaUH5yEobVYmR6vrcan5+beDZTp3IQVpFNiy2oFiDf/VPKmh7iU4zBW2v+n3NURS7WgncGUvvWxlOG3dPDUbM8R9Idlq2T4lIFrHldEmgWsD9m0bcXOu/ZDQOtTYCVC2CUdXgbunNkd5NMni7WD7IPeFeOU1kNmsQ== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 13. 08. 26, 11:01, Mike Rapoport wrote: > From: Pedro Falcato > > From time to time, the following BUG can be observed[0]: > >> kernel BUG at arch/x86/kernel/alternative.c:2576! >> Oops: invalid opcode: 0000 [#1] SMP NOPTI >> CPU: 0 UID: 0 PID: 355 Comm: (udev-worker) Not tainted 7.1.3-1-default #1 PREEMPT(full) openSUSE Tumbleweed 8c1795b03ec64f997e57a8ad38b1161e3b98da64 >> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS unknown 02/02/2022 >> RIP: 0010:__text_poke+0x2aa/0x450 >> Call Trace: >> >> smp_text_poke_batch_finish+0x2a7/0x320 >> __static_call_transform+0xb7/0x220 >> arch_static_call_transform+0x5b/0xb0 >> __static_call_init+0xe9/0x270 >> static_call_module_notify+0x11f/0x150 >> notifier_call_chain+0x61/0xe0 >> blocking_notifier_call_chain_robust+0x63/0xc0 >> load_module+0x1c92/0x20c0 >> init_module_from_file+0xd8/0x140 >> idempotent_init_module+0x100/0x2f0 >> __x64_sys_finit_module+0x71/0xe0 >> do_syscall_64+0xe1/0x610 >> entry_SYSCALL_64_after_hwframe+0x76/0x7e > > which matches the following BUG_ON in alternative.c: > /* > * If something went wrong, crash and burn since recovery paths are not > * implemented. > */ > BUG_ON(!pages[0] || (cross_page_boundary && !pages[1])); > > This can happen if vmalloc_to_page() fails, for any reason. Such can happen > if text poking races with CPA, which can possibly result in the collapsing > of page tables (or breaking of PMD hugepages). It is not a problem for most > users of vmalloc_to_page() (they solely own the vmalloc'd range) but, when > CONFIG_ARCH_HAS_EXECMEM_ROX=y, various modules own a single execmem vmalloc > range, and can call set_memory_*() in parallel on it. This can happen to > race against __text_poke and cause havoc in vmalloc_to_page(). > > Fix it by excluding against CPA using the init_mm mmap read lock. > > Fixes: 64f6a4e10c05 ("x86: re-enable EXECMEM_ROX support") > Reported-by: Jiri Slaby FWIW Tested-by: Jiri Slaby We have not seen any BUGs since applied to the SUSE's kernel. https://bugzilla.suse.com/show_bug.cgi?id=1271202#c26 thanks, -- js suse labs