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=-9.8 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,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 5F711C433E3 for ; Tue, 4 Aug 2020 07:24:36 +0000 (UTC) Received: from whitealder.osuosl.org (smtp1.osuosl.org [140.211.166.138]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 5DE6022C9F for ; Tue, 4 Aug 2020 07:24:36 +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="H40dEn65" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5DE6022C9F Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=virtualization-bounces@lists.linux-foundation.org Received: from localhost (localhost [127.0.0.1]) by whitealder.osuosl.org (Postfix) with ESMTP id 5B5F68708C; Tue, 4 Aug 2020 07:24:35 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from whitealder.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id H8MxG061iqQC; Tue, 4 Aug 2020 07:24:34 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by whitealder.osuosl.org (Postfix) with ESMTP id DACEB86EC9; Tue, 4 Aug 2020 07:24:33 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id BB0DBC0733; Tue, 4 Aug 2020 07:24:33 +0000 (UTC) Received: from hemlock.osuosl.org (smtp2.osuosl.org [140.211.166.133]) by lists.linuxfoundation.org (Postfix) with ESMTP id C8840C0050 for ; Tue, 4 Aug 2020 07:24:31 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by hemlock.osuosl.org (Postfix) with ESMTP id B4DA487A52 for ; Tue, 4 Aug 2020 07:24:31 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from hemlock.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id kVP6Sygk7VL4 for ; Tue, 4 Aug 2020 07:24:31 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from us-smtp-1.mimecast.com (us-smtp-delivery-1.mimecast.com [205.139.110.120]) by hemlock.osuosl.org (Postfix) with ESMTPS id 01D4F86D63 for ; Tue, 4 Aug 2020 07:24:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1596525869; 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=H40dEn65Ut2vHIvs/hvicDda66RPYhWSPkav8KKoGIKCdzTk9Q/vVsi13v12569IclFM68 u6SDKrMsZEgWSqD+9IXCrlKVKvyL7CIuDSEePb+QDC9qzvUfb4RJVCvTAA1T5f3obtzNWx FZBz0wYqoIaNQrc5P35hS4SBj5FEZ0c= 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-266-XGkiJqmiMiCQNKp5Nc9_VA-1; Tue, 04 Aug 2020 03:24:25 -0400 X-MC-Unique: XGkiJqmiMiCQNKp5Nc9_VA-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 5849E10059C2; Tue, 4 Aug 2020 07:24:24 +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 316BF5DA74; Tue, 4 Aug 2020 07:24:22 +0000 (UTC) From: David Hildenbrand To: linux-kernel@vger.kernel.org Subject: [PATCH v3 1/6] mm/page_isolation: don't dump_page(NULL) in set_migratetype_isolate() Date: Tue, 4 Aug 2020 09:24:03 +0200 Message-Id: <20200804072408.5481-2-david@redhat.com> In-Reply-To: <20200804072408.5481-1-david@redhat.com> References: <20200804072408.5481-1-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Cc: Pankaj Gupta , Michal Hocko , Baoquan He , "Michael S . Tsirkin" , virtualization@lists.linux-foundation.org, linux-mm@kvack.org, Qian Cai , Andrew Morton , Mike Kravetz X-BeenThere: virtualization@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Linux virtualization List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: virtualization-bounces@lists.linux-foundation.org Sender: "Virtualization" 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); -- 2.26.2 _______________________________________________ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization