Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932204AbbHKVOI (ORCPT ); Tue, 11 Aug 2015 17:14:08 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:60980 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752438AbbHKVOF (ORCPT ); Tue, 11 Aug 2015 17:14:05 -0400 Date: Tue, 11 Aug 2015 14:14:04 -0700 From: Andrew Morton To: Wanpeng Li Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Naoya Horiguchi Subject: Re: [PATCH] mm/hwpoison: fix panic due to split huge zero page Message-Id: <20150811141404.ecb19c1a66c32abf60d6663c@linux-foundation.org> In-Reply-To: References: X-Mailer: Sylpheed 3.4.1 (GTK+ 2.24.23; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 980 Lines: 23 On Tue, 11 Aug 2015 18:47:57 +0800 Wanpeng Li wrote: > > ... > > Huge zero page is allocated if page fault w/o FAULT_FLAG_WRITE flag. > The get_user_pages_fast() which called in madvise_hwpoison() will get > huge zero page if the page is not allocated before. Huge zero page is > a tranparent huge page, however, it is not an anonymous page. memory_failure > will split the huge zero page and trigger BUG_ON(is_huge_zero_page(page)); > After commit (98ed2b0: mm/memory-failure: give up error handling for > non-tail-refcounted thp), memory_failure will not catch non anon thp > from madvise_hwpoison path and this bug occur. So I'm assuming this patch is needed for 4.2 but not in earlier kernels. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/