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=-6.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 37F1AC2D0F9 for ; Wed, 13 May 2020 10:02:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0959420575 for ; Wed, 13 May 2020 10:02:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1589364166; bh=T7mwNA+BukZCmqrM9ItDpviYepoJkudAyU7T2jHsWvU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=qrSViZ2uWKnshvbhdwIXF0KVcaK2EjRHcSWTGFrG0Ufh3qNQg8tB6Yw1TEMQSvpy1 O5nPRp7maqpK0afHBZE69rjf6YqpuqFgpf6Bhg8h6rbvRbUwzeqTu4bmg/hTXax6KU F3Khqc0KAGHSDn1znUk/fAo5NIRY7OH8Vk5x+XCg= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388212AbgEMKCp (ORCPT ); Wed, 13 May 2020 06:02:45 -0400 Received: from mail.kernel.org ([198.145.29.99]:49146 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732758AbgEMJtu (ORCPT ); Wed, 13 May 2020 05:49:50 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 98712206D6; Wed, 13 May 2020 09:49:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1589363390; bh=T7mwNA+BukZCmqrM9ItDpviYepoJkudAyU7T2jHsWvU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=GqpASOK9TcIIdhCeZDoBTW0N9VxPcp2yXEnh3BdfqsSBTcmiOvzH/bX8UuYC9mxEv 1v+XoOdAqCNKx9Xq3KQNI60Xj4Ilwlb8A9Yz98r3vXgC6IPUjrVvRPFE/pSCmT54Hf unmchlFyn2ruA40wBL97KY6pN+xiWEha6A9PRj8c= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Mark Rutland , Kyrill Tkachov , Will Deacon , Catalin Marinas Subject: [PATCH 5.4 55/90] arm64: hugetlb: avoid potential NULL dereference Date: Wed, 13 May 2020 11:44:51 +0200 Message-Id: <20200513094414.604281798@linuxfoundation.org> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200513094408.810028856@linuxfoundation.org> References: <20200513094408.810028856@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Mark Rutland commit 027d0c7101f50cf03aeea9eebf484afd4920c8d3 upstream. The static analyzer in GCC 10 spotted that in huge_pte_alloc() we may pass a NULL pmdp into pte_alloc_map() when pmd_alloc() returns NULL: | CC arch/arm64/mm/pageattr.o | CC arch/arm64/mm/hugetlbpage.o | from arch/arm64/mm/hugetlbpage.c:10: | arch/arm64/mm/hugetlbpage.c: In function ‘huge_pte_alloc’: | ./arch/arm64/include/asm/pgtable-types.h:28:24: warning: dereference of NULL ‘pmdp’ [CWE-690] [-Wanalyzer-null-dereference] | ./arch/arm64/include/asm/pgtable.h:436:26: note: in expansion of macro ‘pmd_val’ | arch/arm64/mm/hugetlbpage.c:242:10: note: in expansion of macro ‘pte_alloc_map’ | |arch/arm64/mm/hugetlbpage.c:232:10: | |./arch/arm64/include/asm/pgtable-types.h:28:24: | ./arch/arm64/include/asm/pgtable.h:436:26: note: in expansion of macro ‘pmd_val’ | arch/arm64/mm/hugetlbpage.c:242:10: note: in expansion of macro ‘pte_alloc_map’ This can only occur when the kernel cannot allocate a page, and so is unlikely to happen in practice before other systems start failing. We can avoid this by bailing out if pmd_alloc() fails, as we do earlier in the function if pud_alloc() fails. Fixes: 66b3923a1a0f ("arm64: hugetlb: add support for PTE contiguous bit") Signed-off-by: Mark Rutland Reported-by: Kyrill Tkachov Cc: # 4.5.x- Cc: Will Deacon Signed-off-by: Catalin Marinas Signed-off-by: Greg Kroah-Hartman --- arch/arm64/mm/hugetlbpage.c | 2 ++ 1 file changed, 2 insertions(+) --- a/arch/arm64/mm/hugetlbpage.c +++ b/arch/arm64/mm/hugetlbpage.c @@ -230,6 +230,8 @@ pte_t *huge_pte_alloc(struct mm_struct * ptep = (pte_t *)pudp; } else if (sz == (CONT_PTE_SIZE)) { pmdp = pmd_alloc(mm, pudp, addr); + if (!pmdp) + return NULL; WARN_ON(addr & (sz - 1)); /*