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=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no 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 2A22CC4CEC9 for ; Fri, 20 Sep 2019 14:38:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 01F762080F for ; Fri, 20 Sep 2019 14:38:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725830AbfITOhz (ORCPT ); Fri, 20 Sep 2019 10:37:55 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:35762 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388020AbfITOZA (ORCPT ); Fri, 20 Sep 2019 10:25:00 -0400 Received: from [192.168.4.242] (helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1iBJqD-0004wz-P8; Fri, 20 Sep 2019 15:24:57 +0100 Received: from ben by deadeye with local (Exim 4.92.1) (envelope-from ) id 1iBJqC-0007qe-Rj; Fri, 20 Sep 2019 15:24:56 +0100 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, Denis Kirjanov , "Vincenzo Frascino" , "Catalin Marinas" , "Will Deacon" , "Jann Horn" Date: Fri, 20 Sep 2019 15:23:35 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) X-Patchwork-Hint: ignore Subject: [PATCH 3.16 026/132] arm64: compat: Reduce address limit In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.242 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org 3.16.74-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Vincenzo Frascino commit d263119387de9975d2acba1dfd3392f7c5979c18 upstream. Currently, compat tasks running on arm64 can allocate memory up to TASK_SIZE_32 (UL(0x100000000)). This means that mmap() allocations, if we treat them as returning an array, are not compliant with the sections 6.5.8 of the C standard (C99) which states that: "If the expression P points to an element of an array object and the expression Q points to the last element of the same array object, the pointer expression Q+1 compares greater than P". Redefine TASK_SIZE_32 to address the issue. Cc: Catalin Marinas Cc: Will Deacon Cc: Jann Horn Reported-by: Jann Horn Signed-off-by: Vincenzo Frascino [will: fixed typo in comment] Signed-off-by: Will Deacon [bwh: Backported to 3.16: adjust filename] Signed-off-by: Ben Hutchings --- arch/arm64/include/asm/memory.h | 8 ++++++++ 1 file changed, 8 insertions(+) --- a/arch/arm64/include/asm/memory.h +++ b/arch/arm64/include/asm/memory.h @@ -53,7 +53,15 @@ #define TASK_SIZE_64 (UL(1) << VA_BITS) #ifdef CONFIG_COMPAT +#ifdef CONFIG_ARM64_64K_PAGES +/* + * With CONFIG_ARM64_64K_PAGES enabled, the last page is occupied + * by the compat vectors page. + */ #define TASK_SIZE_32 UL(0x100000000) +#else +#define TASK_SIZE_32 (UL(0x100000000) - PAGE_SIZE) +#endif /* CONFIG_ARM64_64K_PAGES */ #define TASK_SIZE (test_thread_flag(TIF_32BIT) ? \ TASK_SIZE_32 : TASK_SIZE_64) #define TASK_SIZE_OF(tsk) (test_tsk_thread_flag(tsk, TIF_32BIT) ? \