Return-Path: Received: from mail-co1nam03on0114.outbound.protection.outlook.com ([104.47.40.114]:38578 "EHLO NAM03-CO1-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S966003AbeCHFD0 (ORCPT ); Thu, 8 Mar 2018 00:03:26 -0500 From: Sasha Levin To: "linux-kernel@vger.kernel.org" , "stable@vger.kernel.org" CC: Naoya Horiguchi , Xiaolong Ye , Chen Gong , Andrew Morton , Linus Torvalds , Sasha Levin Subject: [PATCH AUTOSEL for 4.9 146/190] mm: hwpoison: call shake_page() after try_to_unmap() for mlocked page Date: Thu, 8 Mar 2018 04:59:56 +0000 Message-ID: <20180308045810.8041-146-alexander.levin@microsoft.com> References: <20180308045810.8041-1-alexander.levin@microsoft.com> In-Reply-To: <20180308045810.8041-1-alexander.levin@microsoft.com> Content-Language: en-US Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org List-ID: From: Naoya Horiguchi [ Upstream commit 286c469a988fbaf68e3a97ddf1e6c245c1446968 ] Memory error handler calls try_to_unmap() for error pages in various states. If the error page is a mlocked page, error handling could fail with "still referenced by 1 users" message. This is because the page is linked to and stays in lru cache after the following call chain. try_to_unmap_one page_remove_rmap clear_page_mlock putback_lru_page lru_cache_add memory_failure() calls shake_page() to hanlde the similar issue, but current code doesn't cover because shake_page() is called only before try_to_unmap(). So this patches adds shake_page(). Fixes: 23a003bfd23ea9ea0b7756b920e51f64b284b468 ("mm/madvise: pass return c= ode of memory_failure() to userspace") Link: http://lkml.kernel.org/r/20170417055948.GM31394@yexl-desktop Link: http://lkml.kernel.org/r/1493197841-23986-3-git-send-email-n-horiguch= i@ah.jp.nec.com Signed-off-by: Naoya Horiguchi Reported-by: kernel test robot Cc: Xiaolong Ye Cc: Chen Gong Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin --- mm/memory-failure.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/mm/memory-failure.c b/mm/memory-failure.c index 5aa71a82ca73..851efb004857 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -921,6 +921,7 @@ static int hwpoison_user_mappings(struct page *p, unsig= ned long pfn, int ret; int kill =3D 1, forcekill; struct page *hpage =3D *hpagep; + bool mlocked =3D PageMlocked(hpage); =20 /* * Here we are interested only in user-mapped pages, so skip any @@ -984,6 +985,13 @@ static int hwpoison_user_mappings(struct page *p, unsi= gned long pfn, pr_err("Memory failure: %#lx: failed to unmap page (mapcount=3D%d)\n", pfn, page_mapcount(hpage)); =20 + /* + * try_to_unmap() might put mlocked page in lru cache, so call + * shake_page() again to ensure that it's flushed. + */ + if (mlocked) + shake_page(hpage, 0); + /* * Now that the dirty bit has been propagated to the * struct page and all unmaps done we can decide if --=20 2.14.1