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 X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7E078C07E9A for ; Mon, 12 Jul 2021 21:58:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5DADA61242 for ; Mon, 12 Jul 2021 21:58:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230284AbhGLWBQ (ORCPT ); Mon, 12 Jul 2021 18:01:16 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47074 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229867AbhGLWBP (ORCPT ); Mon, 12 Jul 2021 18:01:15 -0400 Received: from smtp.gentoo.org (mail.gentoo.org [IPv6:2001:470:ea4a:1:5054:ff:fec7:86e4]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4A5E1C0613DD for ; Mon, 12 Jul 2021 14:58:26 -0700 (PDT) Received: by sf.home (Postfix, from userid 1000) id 221D538CBE2B; Mon, 12 Jul 2021 22:58:19 +0100 (BST) From: Sergei Trofimovich To: linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org, Sergei Trofimovich , Andrew Morton , Kees Cook , Alexander Potapenko , Thomas Gleixner , Vlastimil Babka , bowsingbetee@pm.me Subject: [PATCH] mm: page_alloc: fix page_poison=1 / INIT_ON_ALLOC_DEFAULT_ON interaction Date: Mon, 12 Jul 2021 22:58:16 +0100 Message-Id: <20210712215816.1512739-1-slyfox@gentoo.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210712005732.4f9bfa78@zn3> References: <20210712005732.4f9bfa78@zn3> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org To reproduce the failure we need the following system: - kernel command: page_poison=1 init_on_free=0 init_on_alloc=0 - kernel config: * CONFIG_INIT_ON_ALLOC_DEFAULT_ON=y * CONFIG_INIT_ON_FREE_DEFAULT_ON=y * CONFIG_PAGE_POISONING=y 0000000085629bdd: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 0000000022861832: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00000000c597f5b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ CPU: 11 PID: 15195 Comm: bash Kdump: loaded Tainted: G U O 5.13.1-gentoo-x86_64 #1 Hardware name: System manufacturer System Product Name/PRIME Z370-A, BIOS 2801 01/13/2021 Call Trace: dump_stack+0x64/0x7c __kernel_unpoison_pages.cold+0x48/0x84 post_alloc_hook+0x60/0xa0 get_page_from_freelist+0xdb8/0x1000 __alloc_pages+0x163/0x2b0 __get_free_pages+0xc/0x30 pgd_alloc+0x2e/0x1a0 ? dup_mm+0x37/0x4f0 mm_init+0x185/0x270 dup_mm+0x6b/0x4f0 ? __lock_task_sighand+0x35/0x70 copy_process+0x190d/0x1b10 kernel_clone+0xba/0x3b0 __do_sys_clone+0x8f/0xb0 do_syscall_64+0x68/0x80 ? do_syscall_64+0x11/0x80 entry_SYSCALL_64_after_hwframe+0x44/0xae Before the 51cba1eb ("init_on_alloc: Optimize static branches") init_on_alloc never enabled static branch by default. It could only be enabed explicitly by init_mem_debugging_and_hardening(). But after the 51cba1eb static branch could already be enabled by default. There was no code to ever disable it. That caused page_poison=1 / init_on_free=1 conflict. This change extends init_mem_debugging_and_hardening() to also disable static branch disabling. CC: Andrew Morton CC: Kees Cook CC: Alexander Potapenko CC: Thomas Gleixner CC: Vlastimil Babka CC: linux-mm@kvack.org Reported-by: bowsingbetee@pm.me Reported-by: Mikhail Morfikov Fixes: 51cba1eb ("init_on_alloc: Optimize static branches") Signed-off-by: Sergei Trofimovich --- mm/page_alloc.c | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 3b97e17806be..46cb4a9c2b50 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -840,18 +840,22 @@ void init_mem_debugging_and_hardening(void) } #endif - if (_init_on_alloc_enabled_early) { - if (page_poisoning_requested) + if (_init_on_alloc_enabled_early || + IS_ENABLED(CONFIG_INIT_ON_ALLOC_DEFAULT_ON)) { + if (page_poisoning_requested) { pr_info("mem auto-init: CONFIG_PAGE_POISONING is on, " "will take precedence over init_on_alloc\n"); - else + static_branch_disable(&init_on_alloc); + } else static_branch_enable(&init_on_alloc); } - if (_init_on_free_enabled_early) { - if (page_poisoning_requested) + if (_init_on_free_enabled_early || + IS_ENABLED(CONFIG_INIT_ON_FREE_DEFAULT_ON)) { + if (page_poisoning_requested) { pr_info("mem auto-init: CONFIG_PAGE_POISONING is on, " "will take precedence over init_on_free\n"); - else + static_branch_disable(&init_on_free); + } else static_branch_enable(&init_on_free); } -- 2.32.0