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a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1794569215; b=zTMuLZfh2EOWhzfZuGxsaiGtksCvBuWOgphJ/QrrerUQQ3kVNoeJiamVLFhyFj0lQyNQvB 16SahLcni6zzPP1KNaTC8EMNGbxgdeqXeEhG/BiDRUyMV811yQmg4XvF/WrA5YmpxL6qMD 68vzBr3irjw+uakB74vUugX57WN97HE= ARC-Authentication-Results: i=1; imf28.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=FJfBtafa; spf=pass (imf28.hostedemail.com: domain of sashiko-bot@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=sashiko-bot@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id DB07A62710; Fri, 13 Nov 2026 11:26:54 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id CFAF21F000CA; Fri, 13 Nov 2026 11:26:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794569214; bh=ocYzk3NdaX97htiiSe4U1W+aFJaGGkLHqzJNEk6MXeE=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=FJfBtafaQCnHVBG25J2NxFg1iYV8vtdqhAhg5MeHdNzE4fCZzvk7Fm0nev3/GXv/5 y132tppi/C+SC4mvm30b4QJpq5kMozD5hugTJzGO0t/yJ+GndBmY7KMOhkWUOf9AwR XAwrlOtWTFeOjcf1Cle4Ap5Tg+ChSMPLw949sV3POCtD0dSjd02ErdXqmQnas14ybc enkQcfsjP+q5oheQkJ7SirWgAuhSEbCHiJAa3N4v3hsj3eF52wxdHC+lx2ymLfMtGH PWa3Z5ODsKhXRGiA7z50YDyuTmKLoCrewu4BN76B/ha9EjwU8kDEIvKhVEEnBHvkI4 lJVEEdTfZsQRA== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [PATCH v2 6/6] ARM: add CONFIG_VMSPLIT_2G_OPT option Reply-To: sashiko-reviews@lists.linux.dev To: "Arnd Bergmann" , linux-mm@kvack.org Cc: "Arnd Bergmann" , "Andrew Morton" , "Andreas Larsson" , =?utf-8?b?Q2hyaXN0b3BoZSBMZXJveSAoQ1Mg?= =?utf-8?b?R1JPVVAp?= , "Dave Hansen" , =?utf-8?b?RGF2aWQgSGlsZGVuYnJhbmQgKEFybSk=?= , "Jason Gunthorpe" , "Linus Walleij" , =?utf-8?b?TG9yZW56byBTdG9ha2VzIChBUk0p?= , "Matthew Wilcox" , "Malin Jonsson" , "Richard Weinberger" , "Russell King" , x86@kernel.org In-Reply-To: <20261112112528.1116405-7-arnd@kernel.org> References: <20261112112528.1116405-1-arnd@kernel.org> <20261112112528.1116405-7-arnd@kernel.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Fri, 13 Nov 2026 11:26:53 +0000 X-Stat-Signature: puh7uuk788mgafwh1tat4yrwjxxmnwe5 X-Rspamd-Queue-Id: 45A3FC0003 X-Rspam-User: X-Rspamd-Server: rspam08 X-Spam-Status: No, score=-10.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_PASS,SPF_PASS autolearn=ham autolearn_force=no version=4.0.1 X-HE-Tag: 1794569215-157917 X-HE-Meta: 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 SviQ6nBc 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 X-Archived-By: Thank you for your contribution! Sashiko AI review found 1 potential issue to consider: - [Low] ARM: Kconfig: missing PAGE_OFFSET=3D0x70000000 in ARCH_MMAP_RND_BITS_MAX -- commit 174ed2566532b79fdcb5633054674e730fcadf44 Author: Arnd Bergmann ARM: add CONFIG_VMSPLIT_2G_OPT option This commit adds CONFIG_VMSPLIT_2G_OPT with PAGE_OFFSET=3D0x70000000 to provide a full 2 GiB lowmem region on non-LPAE builds, and makes it the default when CONFIG_HIGHMEM is enabled. > diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig > index fee6b7435b7ca..17b4da137a8ea 100644 > --- a/arch/arm/Kconfig > +++ b/arch/arm/Kconfig [ ... ] > @@ -1052,6 +1056,7 @@ config PAGE_OFFSET > hex > default PHYS_OFFSET if !MMU > default 0x40000000 if VMSPLIT_1G > + default 0x70000000 if VMSPLIT_2G_OPT > default 0x80000000 if VMSPLIT_2G > default 0xB0000000 if VMSPLIT_3G_OPT > default 0xC0000000 [Severity: Low] Should ARCH_MMAP_RND_BITS_MAX also handle PAGE_OFFSET=3D0x70000000? arch/arm/Kconfig: config ARCH_MMAP_RND_BITS_MAX default 14 if PAGE_OFFSET=3D0x40000000 default 15 if PAGE_OFFSET=3D0x80000000 default 16 With VMSPLIT_2G_OPT, PAGE_OFFSET=3D0x70000000 falls through to 16 bits (up to 256 MiB of mmap randomization), which is twice the maximum allowed for the larger user address space under PAGE_OFFSET=3D0x80000000. When KASAN is enabled (shrinking TASK_SIZE to 0x5ce00000) and the stack gap reaches MAX_GAP, a 16-bit random offset can exceed STACK_TOP - MAX_GAP in mmap_base() and cause top-down mmap allocations to fall back to bottom-up. --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20261112112528.1116= 405-1-arnd@kernel.org?part=3D6