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 875E6C88E4C for ; Fri, 11 Sep 2026 11:28:59 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 6C4956B008A; Fri, 11 Sep 2026 07:28:56 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 64F9F6B0092; Fri, 11 Sep 2026 07:28:56 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 53CD46B0095; Fri, 11 Sep 2026 07:28:56 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id 207EA6B008A for ; Fri, 11 Sep 2026 07:28:56 -0400 (EDT) Received: from smtpin21.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay01.hostedemail.com (Postfix) with ESMTP id 0D8101C0E6A for ; Fri, 11 Sep 2026 11:28:54 +0000 (UTC) X-FDA: 85201259388.21.0963E44 Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by imf19.hostedemail.com (Postfix) with ESMTP id 5D0DE1A0006 for ; Fri, 11 Sep 2026 11:28:52 +0000 (UTC) Authentication-Results: imf19.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=A2f0gqDW; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf19.hostedemail.com: domain of rppt@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=rppt@kernel.org ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1789126132; b=ZEmERWgygpRydtT7I0GYKwc5DJ6pw6KAISenrnl/iPKVtfGXMKSWqG+u1OtDpw7sAIVhoh QO8ySAiOE6VEkvmCR4QkKHCC7L+4ZVeeKKnR1BU0XeJYX1RsqADIqwTVfLLJtvvFh0h4GQ 4X67ehHubrwA8xcO7tFypTlepnVEX4c= ARC-Authentication-Results: i=1; imf19.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=A2f0gqDW; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf19.hostedemail.com: domain of rppt@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=rppt@kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1789126132; 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: references:dkim-signature; bh=nsSRp8PdyK7jqxwyqAHoe3K2myVb/dPcJ1AFVgoBhm4=; b=YEs9K3gPXWwR3OHlo8poK4QGQhofwGY4K3uxUshdoKDxbwqcltYN3gNqiTIll4TiFQIFTi 5vUPvpqv41F25KUUVRqDNVW4Zt6UgANuM9JdmOh3yJiqn7GptOWtq9nKbBt4f+WCe3ycKT DS9v7jn9eGxjVg+EcFUdfsS5nukgfA0= Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id 55E81415B4; Fri, 11 Sep 2026 11:28:51 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6AF971F0089A; Fri, 11 Sep 2026 11:28:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789126131; bh=nsSRp8PdyK7jqxwyqAHoe3K2myVb/dPcJ1AFVgoBhm4=; h=From:Date:Subject:To:Cc; b=A2f0gqDW7IjntqtLnmWTY9FTZt2kpRTwAR81OQ0+X5rLtkU/oM3woCD8mBXpKl22g FxYe3TsxS68ynHwnCCJsl1bwPDgBbcj3b1Txifi+2tin8nkRKoyJzvInE1BZQaJEX1 SfEvjpltcAkNn5xhvf+Rc0Gw+3IiqappNVYNQ4vVHGBz9KbXFSFUbvXeKjGQTNnKQe oQ8qUrbxCW07kqROwNWcZveAksa3yuRMFG/yhKpWZZTaXd6Lv/XEL9aASh6XtvTLuq biMrXtbaqD7QwD7g67lAzMIJsCVJbU2WmOQf4Qz7SKN0f6wro+FrvrrGb/qQcA7fJ7 xshTLjIDUbIHA== From: "Mike Rapoport (Microsoft)" Date: Fri, 11 Sep 2026 14:28:43 +0300 Subject: [PATCH v2] x86/mm/pat: use pr_warn() for early W^X warnings MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260911-fixes-verify-rwx-v2-1-e2cde39b6693@kernel.org> X-B4-Tracking: v=1; b=H4sIAAAAAAAC/y2O0RKCIBBFf6XhORSRUeyp/2h8AFuVSnQWMh3Hf w+sx7N7z93diAM04MjltBGE2Tgz2gD8fCJNr2wH1NwDE854waqM0dYs4OgcrHal+FkoE0KKTJe FyiUJ2oRwZIJ1q3/s3voBjY89MaGVA6pR2aaPI2+mdJFFOgxx2RvnR1yPh+YslvxvM8kqXuYsE SwwlzSjOE3++gS08EpG7Ei97/sXW54AzNIAAAA= X-Change-ID: 20260910-fixes-verify-rwx-044841b76a38 To: Dave Hansen Cc: Andy Lutomirski , Borislav Petkov , Ihor Solodrai , Ingo Molnar , Mike Rapoport , Nathan Chancellor , "H. Peter Anvin" , Peter Zijlstra , Thomas Gleixner , x86@kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org X-Mailer: b4 0.17-dev X-Rspam-User: X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: 5D0DE1A0006 X-Stat-Signature: osttnbonpkf5i7uipid7s3dsmoo438nf X-HE-Tag: 1789126132-846061 X-HE-Meta: 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 QCcjMyNY vELpCMNHcrc4egVLGB8jJlzk5pfSt1Ar981ZzYVCApAm279gX6MWFDBwIW6DuERLvfCH6Nn7AU0Pm4/ND3DRGsFdcWAbpERcmu+sJkMn8qE7n6f72Y1HPMejZvyqPXEzrwAAKNSfjZLcyS5zljfFfCyhohQvH62Uax+cUi8cFbCxU4BI2i1zjQTX/Cki54mA3LB3hfMzEhiBVvpOox47Wh38uDKzc6CpgQzoBxaP1PtksY3a0v0HMl/yiyuR1LhBJJWeSUiS7hOeu06/+xetdVBcajJMOKaupgBL/cifqT/C207+KTw0r6d3x8hFT6pjKl4vXQQkhhZuw3iw= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Nathan Chancellor reports the following warning: CPA detected W^X violation: 8000000000000123 -> 0000000000000123 range: 0xffffffffc0400000 - 0xffffffffc0400fff PFN 100e00 WARNING: arch/x86/mm/pat/set_memory.c:722 at __change_page_attr_set_clr+0xde7/0x1290, CPU#0: swapper/0/0 Modules linked in: CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted 7.3.0-rc1-debug-00006-g453e78594434 #1 PREEMPT(full) 2950d432dd3910251071a66f3134fe0875432786 Hardware name: ASUS System Product Name/PRIME Z590M-PLUS, BIOS 1801 12/26/2022 RIP: 0010:__change_page_attr_set_clr+0xdff/0x1290 Code: 80 7c 24 42 00 0f 85 3a 04 00 00 48 8d 3d 19 8d 79 02 49 89 d9 4c 89 e1 4c 89 d2 4c 89 f6 4d 8d 84 24 ff 0f 00 00 4c 89 14 24 <67> 48 0f b9 3a 4c 8b 14 24 48 8b 0d 81 44 bf 01 41 f6 c2 01 RSP: 0000:ffffffff87003c60 EFLAGS: 00010246 RAX: 0000000000000002 RBX: 0000000000100e00 RCX: ffffffffc0400000 RDX: 0000000000000123 RSI: 8000000000000123 RDI: ffffffff872e50c0 RBP: 8000000100e00123 R08: ffffffffc0400fff R09: 0000000000100e00 R10: 0000000000000123 R11: 0000000000000001 R12: ffffffffc0400000 R13: 0000000100e00123 R14: 8000000000000123 R15: ffffffff87003d58 FS: 0000000000000000(0000) GS:ffff8ad1777a7000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffff8ad0a4201000 CR3: 00000007e3022001 CR4: 0000000000770ef0 PKRU: 55555554 Call Trace: ? _vm_unmap_aliases+0x219/0x280 change_page_attr_set_clr+0x161/0x250 ? events_sysfs_show+0x5d/0x80 set_memory_x+0x39/0x50 apply_retpolines+0x656/0x6d0 ? events_sysfs_show+0x5d/0x80 ? events_sysfs_show+0x6c/0x80 ? events_sysfs_show+0x62/0x80 alternative_instructions+0x3c/0xd0 arch_cpu_finalize_init+0x130/0x190 start_kernel+0x97d/0xa10 x86_64_start_reservations+0x24/0x30 x86_64_start_kernel+0xda/0xe0 common_startup_64+0x13e/0x151 ---[ end trace 0000000000000000 ]--- The warning appears because commit 038176c21617f ("x86/mm/pat: fix effective RW computation in lookup_address_in_pgd_attr()") fixed the effective RW checked by verify_rwx() and it exposed that pages used for ITS trampolines temporarily have RWX permissions. The permissions are updated in its_fini_core() after all the ITS trampolines are generated, but since verify_rwx() detects invalid transitions, it warns when its_alloc() makes RW memory executable. At the time of alternatives patching the entire kernel text is mapped RWX, so the warning is bogus anyway. Since the verification of the entire page table with debug_checkwx() has to be enabled explicitly in the kernel configuration, retain the warning even if it's bogus, but make it scream less loudly: use pr_warn_once() rather than WARN_ONCE(). The warning can be removed once debug_checkwx() becomes unconditional for configurations with CONFIG_STRICT_KERNEL_RWX set. Reported-by: Nathan Chancellor Closes: https://lore.kernel.org/all/20260905044253.GA3816371@ax162 Signed-off-by: Mike Rapoport (Microsoft) Tested-by: Nathan Chancellor Tested-by: Ihor Solodrai --- Changes in v2: - Use pr_warn_once() for early violations instad if skipping them entirely Link to v1: https://lore.kernel.org/all/20260908092730.4002628-1-rppt@kernel.org/ --- arch/x86/mm/pat/set_memory.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/arch/x86/mm/pat/set_memory.c b/arch/x86/mm/pat/set_memory.c index b3060000da8d1..a4f7fe69e6922 100644 --- a/arch/x86/mm/pat/set_memory.c +++ b/arch/x86/mm/pat/set_memory.c @@ -697,6 +697,21 @@ static inline pgprot_t verify_rwx(pgprot_t old, pgprot_t new, unsigned long star return new; end = start + npg * PAGE_SIZE - 1; + + /* + * If the kernel text is still RWX, gently complain, this could be a + * false positive. + * Once debug_checkwx() becomes mandatory for CONFIG_STRICT_KERNEL_RWX, + * the warning can be removed completely. + */ + if (!kernel_set_to_readonly) { + pr_warn_once(1, "CPA detected W^X violation: %016llx -> %016llx range: 0x%016lx - 0x%016lx PFN %lx\n", + (unsigned long long)pgprot_val(old), + (unsigned long long)pgprot_val(new), + start, end, pfn); + return new; + } + WARN_ONCE(1, "CPA detected W^X violation: %016llx -> %016llx range: 0x%016lx - 0x%016lx PFN %lx\n", (unsigned long long)pgprot_val(old), (unsigned long long)pgprot_val(new), --- base-commit: ebaf7c9bbb1e16523d7036e7e1225ad2dfcc6482 change-id: 20260910-fixes-verify-rwx-044841b76a38 -- Sincerely yours, Mike.