From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f44.google.com (mail-pa0-f44.google.com [209.85.220.44]) by kanga.kvack.org (Postfix) with ESMTP id D5C146B0032 for ; Mon, 20 Apr 2015 17:30:16 -0400 (EDT) Received: by pabsx10 with SMTP id sx10so218903425pab.3 for ; Mon, 20 Apr 2015 14:30:16 -0700 (PDT) Received: from mail.linuxfoundation.org (mail.linuxfoundation.org. [140.211.169.12]) by mx.google.com with ESMTPS id ew2si20687905pbb.152.2015.04.20.14.30.15 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 20 Apr 2015 14:30:16 -0700 (PDT) Date: Mon, 20 Apr 2015 14:30:14 -0700 From: Andrew Morton Subject: Re: [PATCH] mm/memory-failure: call shake_page() when error hits thp tail page Message-Id: <20150420143014.bd6c683d159758db1815799f@linux-foundation.org> In-Reply-To: <1429082714-26115-1-git-send-email-n-horiguchi@ah.jp.nec.com> References: <1429082714-26115-1-git-send-email-n-horiguchi@ah.jp.nec.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Naoya Horiguchi Cc: Dean Nelson , Andi Kleen , Andrea Arcangeli , Hidetoshi Seto , Jin Dongming , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" On Wed, 15 Apr 2015 07:25:46 +0000 Naoya Horiguchi wrote: > Currently memory_failure() calls shake_page() to sweep pages out from pcplists > only when the victim page is 4kB LRU page or thp head page. But we should do > this for a thp tail page too. > Consider that a memory error hits a thp tail page whose head page is on a > pcplist when memory_failure() runs. Then, the current kernel skips shake_pages() > part, so hwpoison_user_mappings() returns without calling split_huge_page() nor > try_to_unmap() because PageLRU of the thp head is still cleared due to the skip > of shake_page(). > As a result, me_huge_page() runs for the thp, which is a broken behavior. > > This patch fixes this problem by calling shake_page() for thp tail case. > > Fixes: 385de35722c9 ("thp: allow a hwpoisoned head page to be put back to LRU") > Signed-off-by: Naoya Horiguchi > Cc: stable@vger.kernel.org # v3.4+ What are the userspace-visible effects of the bug? This info is needed for backporting into -stable and other kernels, please. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org