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=-15.7 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 44374C433B4 for ; Fri, 23 Apr 2021 21:29:00 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id DFAF161468 for ; Fri, 23 Apr 2021 21:28:59 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DFAF161468 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 7E2456B0070; Fri, 23 Apr 2021 17:28:59 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 7BB3D6B0071; Fri, 23 Apr 2021 17:28:59 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 65A616B0072; Fri, 23 Apr 2021 17:28:59 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0138.hostedemail.com [216.40.44.138]) by kanga.kvack.org (Postfix) with ESMTP id 4A0FF6B0070 for ; Fri, 23 Apr 2021 17:28:59 -0400 (EDT) Received: from smtpin39.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 0179418014D04 for ; Fri, 23 Apr 2021 21:28:59 +0000 (UTC) X-FDA: 78064921998.39.A21CEB0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf23.hostedemail.com (Postfix) with ESMTP id 3C085A0000FF for ; Fri, 23 Apr 2021 21:28:56 +0000 (UTC) Received: by mail.kernel.org (Postfix) with ESMTPSA id 780C661469; Fri, 23 Apr 2021 21:28:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1619213337; bh=50DcqW+qXHbwsuPF084kbHU9PE95xeexvEO5iqMPrIM=; h=Date:From:To:Subject:In-Reply-To:From; b=svdMtvwkTn3eNYC4aJvpDAtxgh5Rvq12OJXwlalO/92KOkVH1ihiBkv1RVf1fyzUf ff0syY0NSnLZbF3mWKGiKE44ZjaQNiCqeYLQazOvdvsWRMlyXvr8aoXoBCVB4SHdFv RLWiqtSWM+maAqKZiX2Ie+OZlL20ASJZy2EmRLKY= Date: Fri, 23 Apr 2021 14:28:57 -0700 From: Andrew Morton To: akpm@linux-foundation.org, dchinner@redhat.com, hannes@cmpxchg.org, hch@lst.de, hughd@google.com, jack@suse.cz, kirill.shutemov@linux.intel.com, linux-mm@kvack.org, mm-commits@vger.kernel.org, torvalds@linux-foundation.org, william.kucharski@oracle.com, willy@infradead.org, yang.shi@linux.alibaba.com Subject: [patch 3/5] mm/filemap: fix find_lock_entries hang on 32-bit THP Message-ID: <20210423212857.ZjNcexu9X%akpm@linux-foundation.org> In-Reply-To: <20210423142805.fd6d718ec3296452108b3ee0@linux-foundation.org> User-Agent: s-nail v14.8.16 X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: 3C085A0000FF X-Stat-Signature: y7c834ca3oqjtc44otkyzuzfewd5a486 Received-SPF: none (linux-foundation.org>: No applicable sender policy available) receiver=imf23; identity=mailfrom; envelope-from=""; helo=mail.kernel.org; client-ip=198.145.29.99 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1619213336-48952 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: Hugh Dickins Subject: mm/filemap: fix find_lock_entries hang on 32-bit THP No problem on 64-bit, or without huge pages, but xfstests generic/308 hung uninterruptibly on 32-bit huge tmpfs. Since 4.13's 0cc3b0ec23ce ("Clarify (and fix) MAX_LFS_FILESIZE macros"), MAX_LFS_FILESIZE is only a PAGE_SIZE away from wrapping 32-bit xa_index to 0, so the new find_lock_entries() has to be extra careful when handling a THP. Link: https://lkml.kernel.org/r/alpine.LSU.2.11.2104211735430.3299@eggly.anvils Fixes: 5c211ba29deb ("mm: add and use find_lock_entries") Signed-off-by: Hugh Dickins Cc: Matthew Wilcox Cc: William Kucharski Cc: Christoph Hellwig Cc: Jan Kara Cc: Dave Chinner Cc: Johannes Weiner Cc: "Kirill A. Shutemov" Cc: Yang Shi Signed-off-by: Andrew Morton --- mm/filemap.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) --- a/mm/filemap.c~mm-filemap-fix-find_lock_entries-hang-on-32-bit-thp +++ a/mm/filemap.c @@ -1969,8 +1969,14 @@ unlock: put: put_page(page); next: - if (!xa_is_value(page) && PageTransHuge(page)) - xas_set(&xas, page->index + thp_nr_pages(page)); + if (!xa_is_value(page) && PageTransHuge(page)) { + unsigned int nr_pages = thp_nr_pages(page); + + /* Final THP may cross MAX_LFS_FILESIZE on 32-bit */ + xas_set(&xas, page->index + nr_pages); + if (xas.xa_index < nr_pages) + break; + } } rcu_read_unlock(); _