From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 570CB363C6C; Thu, 2 Jul 2026 05:14:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782969264; cv=none; b=YuEVKHLEUGXZDHiyEkVoREuSdK0pE3S+bsw+fN+nobzkbZ52RCSECHdalSDNvrPrnfNCBCairgw6AZNhXedhJ6vBQSjC414SEVDYg9r0Jey2B675Qlifwoc+MUdfKJCN2nwN4JRicLlsO+e1/1rdhtwOc4p4KlRyt3Sl7P26x9A= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782969264; c=relaxed/simple; bh=T62Rm8CforrQHCgI1jL51VN6OPOgVlXbC7gVEXEkr9w=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Lv5idwzRr1FLgYyhHo0PV993wIRNU5bF+AvdIwHv7zP3Y64MGJPOM94ec410NKfDpjHEkUOhrMsD/XPgLPzz7AVflFCSL9TF4Ggvu78BkmZD75M+vf0cK7YhFr5B+PgfS7T2WXM8Dr2siCrwaVHtSwQ2a1ExSP5BSOEFrvBshVQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b=QOBxtron; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b="QOBxtron" 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 4D6CB3582; Wed, 1 Jul 2026 22:14:17 -0700 (PDT) Received: from cesw-amp-gbt-1s-m12830-01.blr.arm.com (cesw-amp-gbt-1s-m12830-01.blr.arm.com [10.164.195.31]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 218A43F85F; Wed, 1 Jul 2026 22:14:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1782969261; bh=T62Rm8CforrQHCgI1jL51VN6OPOgVlXbC7gVEXEkr9w=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=QOBxtronwSwnHmv9SwXu4hDfj37PApl4TlCG0do4RCYGpXUWt4nD5YqM9fmYpV7+8 Z0BzPJY/0ZDSSsWbBljm+FgtEHXp0U26TjOlmBTEeL/gukZ7RANUd01Z6J9oyC0xTc 4ACwViY/VzUpniG0iOXDyzwZGa6p6YDnhaVNJ4CQ= From: Dev Jain To: muchun.song@linux.dev, osalvador@suse.de, akpm@linux-foundation.org, ljs@kernel.org, david@kernel.org, liam@infradead.org Cc: Dev Jain , riel@surriel.com, vbabka@kernel.org, harry@kernel.org, jannh@google.com, lance.yang@linux.dev, kas@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, rcampbell@nvidia.com, apopple@nvidia.com, ziy@nvidia.com, matthew.brost@intel.com, joshua.hahnjy@gmail.com, rakie.kim@sk.com, byungchul@sk.com, gourry@gourry.net, ying.huang@linux.alibaba.com, j-nomura@ce.jp.nec.com, nao.horiguchi@gmail.com, ak@linux.intel.com, mel@csn.ul.ie, pfalcato@suse.de, jpoimboe@kernel.org, dave.hansen@intel.com, tglx@kernel.org, catalin.marinas@arm.com, will@kernel.org, linux-arm-kernel@lists.infradead.org, ryan.roberts@arm.com, anshuman.khandual@arm.com, stable@vger.kernel.org Subject: [PATCH v2 1/6] arm64: make huge_ptep_get handled unaligned addresses Date: Thu, 2 Jul 2026 05:13:35 +0000 Message-ID: <20260702051341.126509-2-dev.jain@arm.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260702051341.126509-1-dev.jain@arm.com> References: <20260702051341.126509-1-dev.jain@arm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit huge_ptep_get() can be handed a virtual address pointing to the middle of a contpmd/contpte mapped hugetlb folio (examples of callers are pagemap_hugetlb_range, page_mapped_in_vma). The arm64 helper rewalks the pgtables in find_num_contig to answer whether the huge pte we have maps a contpmd or a contpte hugetlb folio, and returns CONT_PMDS or CONT_PTES, so that it can collect a/d bits over the contiguous ptes. We can falsely return CONT_PTES instead of CONT_PMDS if the addr is not aligned. Fix this by aligning the pmdp pointer down to a contpmd base before checking equality with the passed huge pte pointer, to correctly answer whether the huge pte is the base of a contpmd block. Fixes: 29cb80519689 ("arm64: hugetlb: Cleanup huge_pte size discovery mechanisms") Cc: stable@vger.kernel.org Signed-off-by: Dev Jain --- arch/arm64/mm/hugetlbpage.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c index 30772a909aea3..8e799c1fe0aa6 100644 --- a/arch/arm64/mm/hugetlbpage.c +++ b/arch/arm64/mm/hugetlbpage.c @@ -87,7 +87,7 @@ static int find_num_contig(struct mm_struct *mm, unsigned long addr, p4dp = p4d_offset(pgdp, addr); pudp = pud_offset(p4dp, addr); pmdp = pmd_offset(pudp, addr); - if ((pte_t *)pmdp == ptep) { + if ((pte_t *)PTR_ALIGN_DOWN(pmdp, sizeof(*pmdp) * CONT_PMDS) == ptep) { *pgsize = PMD_SIZE; return CONT_PMDS; } -- 2.43.0