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 55511C982FA for ; Mon, 21 Sep 2026 10:58:57 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 1F7126B00AB; Mon, 21 Sep 2026 06:58:56 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 1A8906B0103; Mon, 21 Sep 2026 06:58:56 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 06EDF6B0104; Mon, 21 Sep 2026 06:58:55 -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 D13DE6B00AB for ; Mon, 21 Sep 2026 06:58:55 -0400 (EDT) Received: from smtpin16.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay01.hostedemail.com (Postfix) with ESMTP id C816A1C0184 for ; Mon, 21 Sep 2026 10:58:54 +0000 (UTC) X-FDA: 85237471788.16.C255E24 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by imf22.hostedemail.com (Postfix) with ESMTP id 0BFCFC000B for ; Mon, 21 Sep 2026 10:58:52 +0000 (UTC) Authentication-Results: imf22.hostedemail.com; dkim=pass header.d=arm.com header.s=foss header.b=BThdboLw; spf=pass (imf22.hostedemail.com: domain of yeoreum.yun@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=yeoreum.yun@arm.com; dmarc=pass (policy=none) header.from=arm.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1789988333; 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=r03SVNisaJd6Dqlau4jEcL3AHt7KSVLlnibo546VQzE=; b=ZVcw8t/Rj+ANGzABd/llKPLxhtRSmZKvkD6k5Q1JlpDqEPUN1OZC1vd0H1okaYG9/+gMPR 4tqAhydAqwrnNRAuqxRG3AKJObPEcpwaXs6+jEOfJVk1c4FMK4dYbqEj1cS/1UP8Cwr8be F9V9vLWHzeWNeaM3lYsRsgzGFArj0kg= ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1789988333; b=DYp6QagPGRlT3nwK9Sk3vN1CXkl750Tg09g20266E6e005DyBigDQfKgLwppoX59GKVLrl Ec+523XBtv7lczh3oIYa7DP4CBlTVUIE9Sj4w6teMH/fo9LMjSXWcvipTqjXSM+koZUaL2 KU7E7B1eBv8VbjYl/wiTc2hkJxzMr/M= ARC-Authentication-Results: i=1; imf22.hostedemail.com; dkim=pass header.d=arm.com header.s=foss header.b=BThdboLw; spf=pass (imf22.hostedemail.com: domain of yeoreum.yun@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=yeoreum.yun@arm.com; dmarc=pass (policy=none) header.from=arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id C57631CE0; Mon, 21 Sep 2026 03:58:48 -0700 (PDT) Received: from e129823.arm.com (e129823.arm.com [10.2.213.3]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 12E133F86C; Mon, 21 Sep 2026 03:58:44 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1789988332; bh=dSuJLJ9ohCs7txtQHt7hy5Mg9PfzhT9ZTRhsbp3QTUc=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=BThdboLwJgWaXYoH9hZWEZBjiZRv2Fu3SH7AMV949zk04FGwQM/S7e44T41HHFqBc ig0U/2EjLwcRsv+kn9RsCmeVGvHrzU+JMOsKwYzE5TaT0Ma5zFoMq0vE69LvCBaH9/ 4ET22UaBocVm3SCd1ar8dSE+dmzg+C2+T55N2vcs= From: Yeoreum Yun Date: Mon, 21 Sep 2026 11:55:41 +0100 Subject: [PATCH 19/21] mm/pgtable: disallow calling (pgd|p4d|pud)_page, pgd_page_vaddr() and (p4d|pud)_pgtable with dummy MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260921-dummy_ptxp3-v1-19-cd40cf68242e@arm.com> References: <20260921-dummy_ptxp3-v1-0-cd40cf68242e@arm.com> In-Reply-To: <20260921-dummy_ptxp3-v1-0-cd40cf68242e@arm.com> To: Russell King , Huacai Chen , WANG Xuerui , Thomas Bogendoerfer , Catalin Marinas , Will Deacon , Arnd Bergmann , Andrew Morton , Kairui Song , Qi Zheng , Shakeel Butt , Barry Song , Axel Rasmussen , Yuanchu Xie , Wei Xu , Johannes Weiner , David Hildenbrand , Michal Hocko , Lorenzo Stoakes , Tianrui Zhao , Bibo Mao , Anup Patel , Atish Patra , Paul Walmsley , Palmer Dabbelt , Albert Ou , Alexandre Ghiti , Dave Hansen , Andy Lutomirski , Peter Zijlstra , Thomas Gleixner , Ingo Molnar , Borislav Petkov , x86@kernel.org, "H. Peter Anvin" , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Jonas Bonn , Stefan Kristiansson , Stafford Horne Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, loongarch@lists.linux.dev, linux-mips@vger.kernel.org, linux-arch@vger.kernel.org, linux-mm@kvack.org, kvm@vger.kernel.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-openrisc@vger.kernel.org, Yeoreum Yun X-Mailer: b4 0.13.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=3268; i=yeoreum.yun@arm.com; h=from:subject:message-id; bh=VRD/vI2+dr2wFISWOiD6XpoJffv8Fhm2BOtCv803wXw=; b=owEB7QES/pANAwAKAW3Vw9FaxTEzAcsmYgBqsQ1Tk7kRq4iKLtEgxpTwxLYomoYS7bs7Di2hM iOcaArqGTSJAbMEAAEKAB0WIQQtg+CS3QUzuFh1pJ1t1cPRWsUxMwUCarENUwAKCRBt1cPRWsUx M0sKC/9fNwlXps/S5pQLQVmMhjhsVPzMbJGpnIoLHcK+XvcblaBizi3oEaugKCqA4IADURZxi7N zeU9amkUNdxMyAtLqtqsPRdxMSu+j3HYk690xsRuu/io3DcfvB5D0j/q9hCj04SJ9Bh6IUiV17O gNPS5GYZCwInYoilXG5e+HDU5w+XUwHoO+31YrveczOJESkUQ629XwSLUYzTZszK4UTHSe8eHN7 WpArw7F0ghyhriT0dILPWFsphGS9NifdWOc2+ZQ/1vOfre04d8kJHQb36FIwB6SFR7yI/luwSuw 5RS5NpbJ58nx0AUey7RNro8jvW+HJmYnG9NO6ooeCMeXaKWbwC0g4p0lpKTUN6ZFzwon0SGwno3 YUiLEt32U5HAd7gBIVuvVL/IZo0r+8jfF97cQKOV05fH01cS47H2K1DIwwEQt7PMkVszvEnPgEU pitE91INdVgJpvsLhPH3gte8+ox1sUn6LlA7pzFKeTV7DYzVwjulFjYbnWcQM6VW58Nd8= X-Developer-Key: i=yeoreum.yun@arm.com; a=openpgp; fpr=2D83E092DD0533B85875A49D6DD5C3D15AC53133 X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 0BFCFC000B X-Stat-Signature: mxbqzcbqi9hyy6yt9aogfio6xq8tnfxy X-Rspam-User: X-HE-Tag: 1789988332-875878 X-HE-Meta: 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 6nZEz9Sw HA9yAzwY1Au9WUkOTnLRf9rea09XToP6CVSyg8/ViM/BrH+z3MGTNcL1x6KZzwFh1Q5mDGCyymHfOfCjB3D9IcEcT/ZtZgdxYt4PvmMsoJ12AK75RKUs0pCnoHYdUe8jqn4m3Rz1+fnhLQ2wFI2hlI9S/HfUV3Tv94/QJF5ckx0583nyG2+vgS3ezxU/dlPHG4hVNmFKua8iSs5HMQgwLNaCLn8e55cP3Ms+eNLOBHtQ+phHhT1Pv8wFRdvt4jcERdFq5y7OMGtsnnUW6Z83tC4/5CBdXLycJ5k0tHO4UfwDOMcp5V6Gu3s4jBWKEBlcR0eoB0WGATXqpZIM= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: From: "David Hildenbrand (Arm)" These helpers silently fallback to the folded helpers. With e.g., pdgp_get() returning dummy values, pgd_page_vaddr(pgdp_get(pgdp)) will now behave differently than pgd_page_vaddr(*pgdp). Disallow calling (pgd|p4d|pud)_page() entirely, and catch when passing a dummy value to pgd_page_vaddr() and (p4d|pud)_pgtable. This will catch most abuse of dummy pXdp value at compile time -- so far there were none, and it better stay that way. Signed-off-by: David Hildenbrand (Arm) Co-developed-by: Yeoreum Yun Signed-off-by: Yeoreum Yun --- include/asm-generic/pgtable-nop4d.h | 8 ++++++-- include/asm-generic/pgtable-nopmd.h | 8 ++++++-- include/asm-generic/pgtable-nopud.h | 8 ++++++-- 3 files changed, 18 insertions(+), 6 deletions(-) diff --git a/include/asm-generic/pgtable-nop4d.h b/include/asm-generic/pgtable-nop4d.h index 2d86325235da5..d2dccf7542da5 100644 --- a/include/asm-generic/pgtable-nop4d.h +++ b/include/asm-generic/pgtable-nop4d.h @@ -70,8 +70,12 @@ static __always_inline p4d_t *__p4d_offset_lockless(pgd_t *pgdp, pgd_t pgd, #define p4d_val(x) (pgd_val((x).pgd)) #define __p4d(x) ((p4d_t) { __pgd(x) }) -#define pgd_page(pgd) (p4d_page((p4d_t){ pgd })) -#define pgd_page_vaddr(pgd) ((unsigned long)(p4d_pgtable((p4d_t){ pgd }))) +#define pgd_page(pgd) ({ BUILD_BUG(); (struct page *)NULL; }) +#define pgd_page_vaddr(pgd) \ +({ \ + pgd_check_dummy(pgd); \ + (unsigned long)p4d_pgtable((p4d_t) { pgd }); \ +}) /* * allocating and freeing a p4d is trivial: the 1-entry p4d is diff --git a/include/asm-generic/pgtable-nopmd.h b/include/asm-generic/pgtable-nopmd.h index bd40d3a5743ff..2afbf2d8659dc 100644 --- a/include/asm-generic/pgtable-nopmd.h +++ b/include/asm-generic/pgtable-nopmd.h @@ -79,8 +79,12 @@ static __always_inline pmd_t *__pmd_offset_lockless(pud_t *pudp, pud_t pud, #define pmd_val(x) (pud_val((x).pud)) #define __pmd(x) ((pmd_t) { __pud(x) } ) -#define pud_page(pud) (pmd_page((pmd_t){ pud })) -#define pud_pgtable(pud) ((pmd_t *)(pmd_page_vaddr((pmd_t){ pud }))) +#define pud_page(pud) ({ BUILD_BUG(); (struct page *)NULL; }) +#define pud_pgtable(pud) \ +({ \ + pud_check_dummy(pud); \ + ((pmd_t *)(pmd_page_vaddr((pmd_t) { pud }))); \ +}) /* * allocating and freeing a pmd is trivial: the 1-entry pmd is diff --git a/include/asm-generic/pgtable-nopud.h b/include/asm-generic/pgtable-nopud.h index 7475d0bd0f2e0..3264673c0c386 100644 --- a/include/asm-generic/pgtable-nopud.h +++ b/include/asm-generic/pgtable-nopud.h @@ -77,8 +77,12 @@ static __always_inline pud_t *__pud_offset_lockless(p4d_t *p4dp, p4d_t p4d, #define pud_val(x) (p4d_val((x).p4d)) #define __pud(x) ((pud_t) { __p4d(x) }) -#define p4d_page(p4d) (pud_page((pud_t){ p4d })) -#define p4d_pgtable(p4d) ((pud_t *)(pud_pgtable((pud_t){ p4d }))) +#define p4d_page(p4d) ({ BUILD_BUG(); (struct page *)NULL; }) +#define p4d_pgtable(p4d) \ +({ \ + p4d_check_dummy(p4d); \ + ((pud_t *)(pud_pgtable((pud_t) { p4d }))); \ +}) /* * allocating and freeing a pud is trivial: the 1-entry pud is -- 2.43.0