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=-6.7 required=3.0 tests=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 EF96DC76191 for ; Thu, 18 Jul 2019 12:24:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C6FAB20873 for ; Thu, 18 Jul 2019 12:24:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390246AbfGRMYY (ORCPT ); Thu, 18 Jul 2019 08:24:24 -0400 Received: from mx1.redhat.com ([209.132.183.28]:38868 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390199AbfGRMYY (ORCPT ); Thu, 18 Jul 2019 08:24:24 -0400 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 3A909309264C; Thu, 18 Jul 2019 12:24:24 +0000 (UTC) Received: from redhat.com (ovpn-120-147.rdu2.redhat.com [10.10.120.147]) by smtp.corp.redhat.com (Postfix) with SMTP id 8FA4E60A35; Thu, 18 Jul 2019 12:24:19 +0000 (UTC) Date: Thu, 18 Jul 2019 08:24:11 -0400 From: "Michael S. Tsirkin" To: linux-kernel@vger.kernel.org Cc: Wei Wang , Jason Wang , virtualization@lists.linux-foundation.org, linux-mm@kvack.org Subject: [PATCH v3 1/2] mm/balloon_compaction: avoid duplicate page removal Message-ID: <20190718122324.10552-1-mst@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline X-Mutt-Fcc: =sent X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.43]); Thu, 18 Jul 2019 12:24:24 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Wei Wang A #GP is reported in the guest when requesting balloon inflation via virtio-balloon. The reason is that the virtio-balloon driver has removed the page from its internal page list (via balloon_page_pop), but balloon_page_enqueue_one also calls "list_del" to do the removal. This is necessary when it's used from balloon_page_enqueue_list, but not from balloon_page_enqueue. Move list_del to balloon_page_enqueue, and update comments accordingly. Fixes: 418a3ab1e778 (mm/balloon_compaction: List interfaces) Signed-off-by: Wei Wang Signed-off-by: Michael S. Tsirkin --- mm/balloon_compaction.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/mm/balloon_compaction.c b/mm/balloon_compaction.c index 83a7b614061f..d25664e1857b 100644 --- a/mm/balloon_compaction.c +++ b/mm/balloon_compaction.c @@ -21,7 +21,6 @@ static void balloon_page_enqueue_one(struct balloon_dev_info *b_dev_info, * memory corruption is possible and we should stop execution. */ BUG_ON(!trylock_page(page)); - list_del(&page->lru); balloon_page_insert(b_dev_info, page); unlock_page(page); __count_vm_event(BALLOON_INFLATE); @@ -47,6 +46,7 @@ size_t balloon_page_list_enqueue(struct balloon_dev_info *b_dev_info, spin_lock_irqsave(&b_dev_info->pages_lock, flags); list_for_each_entry_safe(page, tmp, pages, lru) { + list_del(&page->lru); balloon_page_enqueue_one(b_dev_info, page); n_pages++; } @@ -128,13 +128,19 @@ struct page *balloon_page_alloc(void) EXPORT_SYMBOL_GPL(balloon_page_alloc); /* - * balloon_page_enqueue - allocates a new page and inserts it into the balloon - * page list. + * balloon_page_enqueue - inserts a new page into the balloon page list. + * * @b_dev_info: balloon device descriptor where we will insert a new page to * @page: new page to enqueue - allocated using balloon_page_alloc. * * Driver must call it to properly enqueue a new allocated balloon page * before definitively removing it from the guest system. + * + * Drivers must not call balloon_page_enqueue on pages that have been + * pushed to a list with balloon_page_push before removing them with + * balloon_page_pop. To all pages on a list, use balloon_page_list_enqueue + * instead. + * * This function returns the page address for the recently enqueued page or * NULL in the case we fail to allocate a new page this turn. */ -- MST