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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 DDEABC433E6 for ; Tue, 29 Dec 2020 23:14:43 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 91F6422227 for ; Tue, 29 Dec 2020 23:14:43 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 91F6422227 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 2E8978D0075; Tue, 29 Dec 2020 18:14:43 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 299C88D006A; Tue, 29 Dec 2020 18:14:43 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 1618C8D0075; Tue, 29 Dec 2020 18:14:43 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0194.hostedemail.com [216.40.44.194]) by kanga.kvack.org (Postfix) with ESMTP id ED0E28D006A for ; Tue, 29 Dec 2020 18:14:42 -0500 (EST) Received: from smtpin15.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id AF3793623 for ; Tue, 29 Dec 2020 23:14:42 +0000 (UTC) X-FDA: 77647876404.15.sail07_5a06c0f274a0 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin15.hostedemail.com (Postfix) with ESMTP id 8EFA21814B0C1 for ; Tue, 29 Dec 2020 23:14:42 +0000 (UTC) X-HE-Tag: sail07_5a06c0f274a0 X-Filterd-Recvd-Size: 2737 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf11.hostedemail.com (Postfix) with ESMTP for ; Tue, 29 Dec 2020 23:14:42 +0000 (UTC) Received: by mail.kernel.org (Postfix) with ESMTPSA id EE52B2222A; Tue, 29 Dec 2020 23:14:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1609283681; bh=h4KxPNu8JUKNQQue82eivjsaXfmQO5zgNGJKT/TWOVw=; h=Date:From:To:Subject:In-Reply-To:From; b=1dYzjBhyjsGZwVbN6FDf7EZFm3S97O3O9Qty48RIN2gk1fWXJV3fnjA5bPBLlktZV QVldDSxaWRJ6VeJtrE/OLT8XM2dI+Xb7ax+9dwV0usueNss9bq5oZvqdJG0KctoCl2 AJzPsrt00JnUv9TxWs8z6LAla4b4VuORxsQX+79E= Date: Tue, 29 Dec 2020 15:14:40 -0800 From: Andrew Morton To: akpm@linux-foundation.org, deller@gmx.de, kaleshsingh@google.com, kirill.shutemov@linux.intel.com, linux-mm@kvack.org, linux@roeck-us.net, lokeshgidra@google.com, minchan@kernel.org, mm-commits@vger.kernel.org, surenb@google.com, torvalds@linux-foundation.org Subject: [patch 07/16] mm/mremap.c: fix extent calculation Message-ID: <20201229231440.q8f_qyKwg%akpm@linux-foundation.org> In-Reply-To: <20201229151349.3285926ec0d1f65a27ac8534@linux-foundation.org> User-Agent: s-nail v14.8.16 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: Kalesh Singh Subject: mm/mremap.c: fix extent calculation When `next < old_addr`, `next - old_addr` arithmetic underflows causing `extent` to be incorrect. Make `extent` the smaller of `next - old_addr` or `old_end - old_addr`. Link: https://lkml.kernel.org/r/20201219170433.2418867-1-kaleshsingh@google.com Fixes: c49dd34018026 ("mm: speedup mremap on 1GB or larger regions") Signed-off-by: Kalesh Singh Reported-by: Guenter Roeck Tested-by: Guenter Roeck Cc: Suren Baghdasaryan Cc: Minchan Kim Cc: Lokesh Gidra Cc: Helge Deller Cc: Kalesh Singh Cc: "Kirill A. Shutemov" Signed-off-by: Andrew Morton --- mm/mremap.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/mm/mremap.c~mm-mremap-fix-extent-calculation +++ a/mm/mremap.c @@ -358,7 +358,9 @@ static unsigned long get_extent(enum pgt next = (old_addr + size) & mask; /* even if next overflowed, extent below will be ok */ - extent = (next > old_end) ? old_end - old_addr : next - old_addr; + extent = next - old_addr; + if (extent > old_end - old_addr) + extent = old_end - old_addr; next = (new_addr + size) & mask; if (extent > next - new_addr) extent = next - new_addr; _