From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg Kroah-Hartman , alan@lxorguk.ukuu.org.uk, Naoya Horiguchi , Andi Kleen , Tony Luck , Andi Kleen , Wu Fengguang , Andrew Morton , Linus Torvalds Subject: [ 07/20] mm: soft offline: split thp at the beginning of soft_offline_page() Date: Thu, 6 Dec 2012 16:54:22 -0800 Message-Id: <20121207005234.885301524@linuxfoundation.org> In-Reply-To: <20121207005232.756641002@linuxfoundation.org> References: <20121207005232.756641002@linuxfoundation.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.4-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: Greg Kroah-Hartman --- mm/memory-failure.c | 8 ++++++++ 1 file changed, 8 insertions(+) --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -1481,9 +1481,17 @@ int soft_offline_page(struct page *page, { 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)