From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, UNPARSEABLE_RELAY,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4A365CA9EC6 for ; Wed, 30 Oct 2019 16:59:04 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 0A82C2054F for ; Wed, 30 Oct 2019 16:59:04 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0A82C2054F Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id AC4EF6B0269; Wed, 30 Oct 2019 12:59:03 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id AA7726B026F; Wed, 30 Oct 2019 12:59:03 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 9FFBD6B0270; Wed, 30 Oct 2019 12:59:03 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0178.hostedemail.com [216.40.44.178]) by kanga.kvack.org (Postfix) with ESMTP id 7FF666B0269 for ; Wed, 30 Oct 2019 12:59:03 -0400 (EDT) Received: from smtpin17.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with SMTP id 18E7F181AEF23 for ; Wed, 30 Oct 2019 16:59:03 +0000 (UTC) X-FDA: 76101060966.17.frame38_6c02740e1c22d X-HE-Tag: frame38_6c02740e1c22d X-Filterd-Recvd-Size: 3686 Received: from out30-42.freemail.mail.aliyun.com (out30-42.freemail.mail.aliyun.com [115.124.30.42]) by imf25.hostedemail.com (Postfix) with ESMTP for ; Wed, 30 Oct 2019 16:59:01 +0000 (UTC) X-Alimail-AntiSpam:AC=PASS;BC=-1|-1;BR=01201311R111e4;CH=green;DM=||false|;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e07486;MF=yang.shi@linux.alibaba.com;NM=1;PH=DS;RN=9;SR=0;TI=SMTPD_---0Tgiqt6T_1572454731; Received: from e19h19392.et15sqa.tbsite.net(mailfrom:yang.shi@linux.alibaba.com fp:SMTPD_---0Tgiqt6T_1572454731) by smtp.aliyun-inc.com(127.0.0.1); Thu, 31 Oct 2019 00:58:58 +0800 From: Yang Shi To: lixinhai.lxh@gmail.com, vbabka@suse.cz, mhocko@suse.com, mgorman@techsingularity.net, akpm@linux-foundation.org Cc: yang.shi@linux.alibaba.com, stable@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [PATCH] mm: mempolicy: fix the wrong return value and potential pages leak of mbind Date: Thu, 31 Oct 2019 00:58:51 +0800 Message-Id: <1572454731-3925-1-git-send-email-yang.shi@linux.alibaba.com> X-Mailer: git-send-email 1.8.3.1 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: The commit d883544515aa ("mm: mempolicy: make the behavior consistent when MPOL_MF_MOVE* and MPOL_MF_STRICT were specified") fixed the return value of mbind() for a couple of corner cases. But, it altered the errno for some other cases, for example, mbind() should return -EFAULT when part or all of the memory range specified by nodemask and maxnode points outside your accessible address space, or there was an unmapped hole in the specified memory range specified by addr and len. Fixed this by preserving the errno returned by queue_pages_range(). And, the pagelist may be not empty even though queue_pages_range() returns error, put the pages back to LRU since mbind_range() is not called to really apply the policy so those pages should not be migrated, this is also the old behavior before the problematic commit. Reported-by: Li Xinhai Cc: Vlastimil Babka Cc: Michal Hocko Cc: Mel Gorman Cc: v4.19 and v5.2+ Signed-off-by: Yang Shi --- mm/mempolicy.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-) diff --git a/mm/mempolicy.c b/mm/mempolicy.c index 4ae967b..e08c941 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -672,7 +672,9 @@ static int queue_pages_test_walk(unsigned long start, unsigned long end, * 1 - there is unmovable page, but MPOL_MF_MOVE* & MPOL_MF_STRICT were * specified. * 0 - queue pages successfully or no misplaced page. - * -EIO - there is misplaced page and only MPOL_MF_STRICT was specified. + * errno - i.e. misplaced pages with MPOL_MF_STRICT specified (-EIO) or + * memory range specified by nodemask and maxnode points outside + * your accessible address space (-EFAULT) */ static int queue_pages_range(struct mm_struct *mm, unsigned long start, unsigned long end, @@ -1286,7 +1288,7 @@ static long do_mbind(unsigned long start, unsigned long len, flags | MPOL_MF_INVERT, &pagelist); if (ret < 0) { - err = -EIO; + err = ret; goto up_out; } @@ -1305,10 +1307,12 @@ static long do_mbind(unsigned long start, unsigned long len, if ((ret > 0) || (nr_failed && (flags & MPOL_MF_STRICT))) err = -EIO; - } else - putback_movable_pages(&pagelist); - + } else { up_out: + if (!list_empty(&pagelist)) + putback_movable_pages(&pagelist); + } + up_write(&mm->mmap_sem); mpol_out: mpol_put(new); -- 1.8.3.1