From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755286Ab2LCOgG (ORCPT ); Mon, 3 Dec 2012 09:36:06 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:43654 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932072Ab2LCOgB (ORCPT ); Mon, 3 Dec 2012 09:36:01 -0500 Message-Id: <20121203143159.879481717@decadent.org.uk> User-Agent: quilt/0.60-1 Date: Mon, 03 Dec 2012 14:33:12 +0000 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Naoya Horiguchi , Andi Kleen , Tony Luck , Andi Kleen , Wu Fengguang , Linus Torvalds Subject: [ 86/89] mm: soft offline: split thp at the beginning of soft_offline_page() In-Reply-To: <20121203143146.549859007@decadent.org.uk> X-SA-Exim-Connect-IP: 2001:470:1f08:1539:21c:bfff:fe03:f805 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Naoya Horiguchi commit 783657a7dc20e5c0efbc9a09a9dd38e238a723da upstream. When we try to soft-offline a thp tail page, put_page() is called on the tail page unthinkingly and VM_BUG_ON is triggered in put_compound_page(). This patch splits thp before going into the main body of soft-offlining. Signed-off-by: Naoya Horiguchi Cc: Andi Kleen Cc: Tony Luck Cc: Andi Kleen Cc: Wu Fengguang Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Ben Hutchings --- mm/memory-failure.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/mm/memory-failure.c b/mm/memory-failure.c index 6c5899b..8b20278 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -1476,9 +1476,17 @@ int soft_offline_page(struct page *page, int flags) { int ret; unsigned long pfn = page_to_pfn(page); + struct page *hpage = compound_trans_head(page); if (PageHuge(page)) return soft_offline_huge_page(page, flags); + if (PageTransHuge(hpage)) { + if (PageAnon(hpage) && unlikely(split_huge_page(hpage))) { + pr_info("soft offline: %#lx: failed to split THP\n", + pfn); + return -EBUSY; + } + } ret = get_any_page(page, pfn, flags); if (ret < 0)