From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wr0-f198.google.com (mail-wr0-f198.google.com [209.85.128.198]) by kanga.kvack.org (Postfix) with ESMTP id CFE3D6B0038 for ; Fri, 1 Dec 2017 10:22:13 -0500 (EST) Received: by mail-wr0-f198.google.com with SMTP id o20so5880536wro.8 for ; Fri, 01 Dec 2017 07:22:13 -0800 (PST) Received: from mx2.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id f22si3809273eda.157.2017.12.01.07.22.12 for (version=TLS1 cipher=AES128-SHA bits=128/128); Fri, 01 Dec 2017 07:22:12 -0800 (PST) Subject: Re: [patch 04/15] mm/mempolicy: add nodes_empty check in SYSC_migrate_pages References: <5a2082fa.bXLNoQ4bvY4J0ImP%akpm@linux-foundation.org> From: Vlastimil Babka Message-ID: <238af2fe-e8c2-5fe5-aa5b-1361e334058b@suse.cz> Date: Fri, 1 Dec 2017 16:20:46 +0100 MIME-Version: 1.0 In-Reply-To: <5a2082fa.bXLNoQ4bvY4J0ImP%akpm@linux-foundation.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: akpm@linux-foundation.org, linux-mm@kvack.org, xieyisheng1@huawei.com, ak@linux.intel.com, cl@linux.com, mingo@kernel.org, n-horiguchi@ah.jp.nec.com, rientjes@google.com, salls@cs.ucsb.edu, tanxiaojun@huawei.com On 11/30/2017 11:15 PM, akpm@linux-foundation.org wrote: > From: Yisheng Xie > Subject: mm/mempolicy: add nodes_empty check in SYSC_migrate_pages > > As in manpage of migrate_pages, the errno should be set to EINVAL when > none of the node IDs specified by new_nodes are on-line and allowed by the > process's current cpuset context, or none of the specified nodes contain > memory. However, when test by following case: > > new_nodes = 0; > old_nodes = 0xf; > ret = migrate_pages(pid, old_nodes, new_nodes, MAX); > > The ret will be 0 and no errno is set. As the new_nodes is empty, we > should expect EINVAL as documented. > > To fix the case like above, this patch check whether target nodes AND > current task_nodes is empty, and then check whether AND > node_states[N_MEMORY] is empty. > > Link: http://lkml.kernel.org/r/1510882624-44342-4-git-send-email-xieyisheng1@huawei.com > Signed-off-by: Yisheng Xie > Cc: Andi Kleen > Cc: Chris Salls > Cc: Christopher Lameter > Cc: David Rientjes > Cc: Ingo Molnar > Cc: Naoya Horiguchi > Cc: Tan Xiaojun > Cc: Vlastimil Babka > Signed-off-by: Andrew Morton My previous concerns here were a mistake as I explained in my reply to v4. So you can add Acked-by: Vlastimil Babka and proceed with the series. Thanks. > --- > > mm/mempolicy.c | 10 +++++++--- > 1 file changed, 7 insertions(+), 3 deletions(-) > > diff -puN mm/mempolicy.c~mm-mempolicy-add-nodes_empty-check-in-sysc_migrate_pages mm/mempolicy.c > --- a/mm/mempolicy.c~mm-mempolicy-add-nodes_empty-check-in-sysc_migrate_pages > +++ a/mm/mempolicy.c > @@ -1433,10 +1433,14 @@ SYSCALL_DEFINE4(migrate_pages, pid_t, pi > goto out_put; > } > > - if (!nodes_subset(*new, node_states[N_MEMORY])) { > - err = -EINVAL; > + task_nodes = cpuset_mems_allowed(current); > + nodes_and(*new, *new, task_nodes); > + if (nodes_empty(*new)) > + goto out_put; > + > + nodes_and(*new, *new, node_states[N_MEMORY]); > + if (nodes_empty(*new)) > goto out_put; > - } > > err = security_task_movememory(task); > if (err) > _ > -- 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