From patchwork Tue Aug 4 19:41:37 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Hildenbrand X-Patchwork-Id: 11700951 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id A88FE722 for ; Tue, 4 Aug 2020 19:42:03 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 8C2E52076E for ; Tue, 4 Aug 2020 19:42:03 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="HmvIsjv+" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8C2E52076E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id A5C048D0183; Tue, 4 Aug 2020 15:42:01 -0400 (EDT) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id 995B48D0081; Tue, 4 Aug 2020 15:42:01 -0400 (EDT) X-Original-To: int-list-linux-mm@kvack.org X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 85C3D8D0183; Tue, 4 Aug 2020 15:42:01 -0400 (EDT) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0135.hostedemail.com [216.40.44.135]) by kanga.kvack.org (Postfix) with ESMTP id 6CA738D0081 for ; Tue, 4 Aug 2020 15:42:01 -0400 (EDT) Received: from smtpin08.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 3053F8248047 for ; Tue, 4 Aug 2020 19:42:01 +0000 (UTC) X-FDA: 77113906842.08.steel61_0b1808e26fa9 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin08.hostedemail.com (Postfix) with ESMTP id 0BB9A1819E772 for ; Tue, 4 Aug 2020 19:42:01 +0000 (UTC) X-Spam-Summary: 1,0,0,,d41d8cd98f00b204,david@redhat.com,,RULES_HIT:30054:30064,0,RBL:205.139.110.120:@redhat.com:.lbl8.mailshell.net-66.10.201.10 62.18.0.100;04yfxafc7m7w9nx338rfgjk98oxhnypim6fyq99wseagerwtm8hoke4jkmczymx.k6cha75jofqcn5ehqbpw8fqgxitgzqu6xe5f9r7os5ncixsi1uzmjngpc34xc56.y-lbl8.mailshell.net-223.238.255.100,CacheIP:none,Bayesian:0.5,0.5,0.5,Netcheck:none,DomainCache:0,MSF:not bulk,SPF:ft,MSBL:0,DNSBL:none,Custom_rules:0:0:0,LFtime:27,LUA_SUMMARY:none X-HE-Tag: steel61_0b1808e26fa9 X-Filterd-Recvd-Size: 4093 Received: from us-smtp-1.mimecast.com (us-smtp-delivery-1.mimecast.com [205.139.110.120]) by imf16.hostedemail.com (Postfix) with ESMTP for ; Tue, 4 Aug 2020 19:42:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1596570120; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=dyDrSr/R3IYIedmMJp2EbzPQ1RIZu9oQIJgsVrWfxkI=; b=HmvIsjv+in567DKqdxvnyHXqMKSfgF50vPzelMQxzgUjcvv6D6w/5QzJl1bNDtikDG52ko leuamC8TnPlamTlpHnVixhiujETl0wXnY8FzC3Qr0oe/tJLdiMb6ROkwAU9KqvMhrPrFN1 cbgNxAmD1k3eOPFhT53K3SqW9QpgEqY= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-98-9Z2g_H3fPSev2zFAXNtB6A-1; Tue, 04 Aug 2020 15:41:58 -0400 X-MC-Unique: 9Z2g_H3fPSev2zFAXNtB6A-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id EBE488015F3; Tue, 4 Aug 2020 19:41:56 +0000 (UTC) Received: from t480s.redhat.com (ovpn-113-95.ams2.redhat.com [10.36.113.95]) by smtp.corp.redhat.com (Postfix) with ESMTP id BCF3672E4F; Tue, 4 Aug 2020 19:41:54 +0000 (UTC) From: David Hildenbrand To: linux-kernel@vger.kernel.org Cc: virtualization@lists.linux-foundation.org, linux-mm@kvack.org, David Hildenbrand , Baoquan He , Pankaj Gupta , Mike Kravetz , Andrew Morton , Michal Hocko , "Michael S . Tsirkin" , Qian Cai Subject: [PATCH v4 1/6] mm/page_isolation: don't dump_page(NULL) in set_migratetype_isolate() Date: Tue, 4 Aug 2020 21:41:37 +0200 Message-Id: <20200804194142.28279-2-david@redhat.com> In-Reply-To: <20200804194142.28279-1-david@redhat.com> References: <20200804194142.28279-1-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Rspamd-Queue-Id: 0BB9A1819E772 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam05 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: Right now, if we have two isolations racing, we might trigger the WARN_ON_ONCE() and to dump_page(NULL), dereferencing NULL. Let's just return directly. In the future, we might want to report -EAGAIN to the caller instead, as this could indicate a temporary isolation failure only. Reviewed-by: Baoquan He Reviewed-by: Pankaj Gupta Acked-by: Mike Kravetz Fixes: 4a55c0474a92 ("mm/hotplug: silence a lockdep splat with printk()") Cc: Andrew Morton Cc: Michal Hocko Cc: Michael S. Tsirkin Cc: Qian Cai Signed-off-by: David Hildenbrand --- mm/page_isolation.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/mm/page_isolation.c b/mm/page_isolation.c index f6d07c5f0d34d..7d7d263ce7f4b 100644 --- a/mm/page_isolation.c +++ b/mm/page_isolation.c @@ -29,10 +29,12 @@ static int set_migratetype_isolate(struct page *page, int migratetype, int isol_ /* * We assume the caller intended to SET migrate type to isolate. * If it is already set, then someone else must have raced and - * set it before us. Return -EBUSY + * set it before us. */ - if (is_migrate_isolate_page(page)) - goto out; + if (is_migrate_isolate_page(page)) { + spin_unlock_irqrestore(&zone->lock, flags); + return -EBUSY; + } /* * FIXME: Now, memory hotplug doesn't call shrink_slab() by itself. @@ -52,7 +54,6 @@ static int set_migratetype_isolate(struct page *page, int migratetype, int isol_ ret = 0; } -out: spin_unlock_irqrestore(&zone->lock, flags); if (!ret) { drain_all_pages(zone);