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=-15.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 C7754C4BA00 for ; Mon, 28 Jun 2021 15:28:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BFE7461C6A for ; Mon, 28 Jun 2021 15:28:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238510AbhF1P37 (ORCPT ); Mon, 28 Jun 2021 11:29:59 -0400 Received: from outbound-smtp19.blacknight.com ([46.22.139.246]:45525 "EHLO outbound-smtp19.blacknight.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237031AbhF1PEs (ORCPT ); Mon, 28 Jun 2021 11:04:48 -0400 Received: from mail.blacknight.com (pemlinmail05.blacknight.ie [81.17.254.26]) by outbound-smtp19.blacknight.com (Postfix) with ESMTPS id 40B3D1C354A for ; Mon, 28 Jun 2021 16:02:21 +0100 (IST) Received: (qmail 19484 invoked from network); 28 Jun 2021 15:02:20 -0000 Received: from unknown (HELO techsingularity.net) (mgorman@techsingularity.net@[84.203.17.255]) by 81.17.254.9 with ESMTPSA (AES256-SHA encrypted, authenticated); 28 Jun 2021 15:02:20 -0000 Date: Mon, 28 Jun 2021 16:02:19 +0100 From: Mel Gorman To: Andrew Morton Cc: Dave Jones , Dan Carpenter , Jesper Dangaard Brouer , Vlastimil Babka , Linux-MM , LKML , Linus Torvalds Subject: [PATCH] mm/page_alloc: Correct return value of populated elements if bulk array is populated Message-ID: <20210628150219.GC3840@techsingularity.net> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Dave Jones reported the following This made it into 5.13 final, and completely breaks NFSD for me (Serving tcp v3 mounts). Existing mounts on clients hang, as do new mounts from new clients. Rebooting the server back to rc7 everything recovers. The commit b3b64ebd3822 ("mm/page_alloc: do bulk array bounds check after checking populated elements") returns the wrong value if the array is already populated which is interpreted as an allocation failure. Dave reported this fixes his problem and it also passed a test running dbench over NFS. Fixes: b3b64ebd3822 ("mm/page_alloc: do bulk array bounds check after checking populated elements") Reported-and-tested-by: Dave Jones Signed-off-by: Mel Gorman Cc: [5.13+] --- mm/page_alloc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index ef2265f86b91..04220581579c 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -5058,7 +5058,7 @@ unsigned long __alloc_pages_bulk(gfp_t gfp, int preferred_nid, /* Already populated array? */ if (unlikely(page_array && nr_pages - nr_populated == 0)) - return 0; + return nr_populated; /* Use the single page allocator for one page. */ if (nr_pages - nr_populated == 1)