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=-6.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham 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 C00CDCA90AF for ; Wed, 13 May 2020 10:01:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 96CAC20575 for ; Wed, 13 May 2020 10:01:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1589364068; bh=bRprwhULdLSmMkWbpcyasmCDFpAt5pBcEH9Ox3Ydgq8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=Ur/F1Ij/6PrueTt+JmaicI+PnB6UdXTKJmUlmzuM7he4q+jCTbdEQYAo38YylBaeh ZJrznKhTxw4ye3eWmRI9umwXuz7ZeNayKrzoEdZq8o4zc5Xp/VXej2XWop9KiCS+n/ am18o2utT55CKOs5aEiY9XJTbnRXJOe0w99IiIss= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388606AbgEMKBH (ORCPT ); Wed, 13 May 2020 06:01:07 -0400 Received: from mail.kernel.org ([198.145.29.99]:52256 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732597AbgEMJv1 (ORCPT ); Wed, 13 May 2020 05:51:27 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 6D6BE20575; Wed, 13 May 2020 09:51:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1589363486; bh=bRprwhULdLSmMkWbpcyasmCDFpAt5pBcEH9Ox3Ydgq8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=TOdhm98QoyN1zxiihXFvHogMlKEGTF4lYqlyvijl70CHODg3X/lXdQb7j+4AsX4Dj vYaHVaPZ4KM2GL5JQ/vqpummv4jtIrSeZHSAEFQe4UMDqm7UStywI0UjpyXf8LvEQb gA7QLRqoqkyvww+rIqgwhRxYSSA85Iwm/ZwVlke8= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Matthew Wilcox , Yafang Shao , Andrew Morton , Michal Hocko , Johannes Weiner , Vladimir Davydov , Linus Torvalds Subject: [PATCH 5.4 86/90] mm, memcg: fix error return value of mem_cgroup_css_alloc() Date: Wed, 13 May 2020 11:45:22 +0200 Message-Id: <20200513094418.119037500@linuxfoundation.org> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200513094408.810028856@linuxfoundation.org> References: <20200513094408.810028856@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Yafang Shao commit 11d6761218d19ca06ae5387f4e3692c4fa9e7493 upstream. When I run my memcg testcase which creates lots of memcgs, I found there're unexpected out of memory logs while there're still enough available free memory. The error log is mkdir: cannot create directory 'foo.65533': Cannot allocate memory The reason is when we try to create more than MEM_CGROUP_ID_MAX memcgs, an -ENOMEM errno will be set by mem_cgroup_css_alloc(), but the right errno should be -ENOSPC "No space left on device", which is an appropriate errno for userspace's failed mkdir. As the errno really misled me, we should make it right. After this patch, the error log will be mkdir: cannot create directory 'foo.65533': No space left on device [akpm@linux-foundation.org: s/EBUSY/ENOSPC/, per Michal] [akpm@linux-foundation.org: s/EBUSY/ENOSPC/, per Michal] Fixes: 73f576c04b94 ("mm: memcontrol: fix cgroup creation failure after many small jobs") Suggested-by: Matthew Wilcox Signed-off-by: Yafang Shao Signed-off-by: Andrew Morton Acked-by: Michal Hocko Acked-by: Johannes Weiner Cc: Vladimir Davydov Link: http://lkml.kernel.org/r/20200407063621.GA18914@dhcp22.suse.cz Link: http://lkml.kernel.org/r/1586192163-20099-1-git-send-email-laoar.shao@gmail.com Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- mm/memcontrol.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-) --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -5101,19 +5101,22 @@ static struct mem_cgroup *mem_cgroup_all unsigned int size; int node; int __maybe_unused i; + long error = -ENOMEM; size = sizeof(struct mem_cgroup); size += nr_node_ids * sizeof(struct mem_cgroup_per_node *); memcg = kzalloc(size, GFP_KERNEL); if (!memcg) - return NULL; + return ERR_PTR(error); memcg->id.id = idr_alloc(&mem_cgroup_idr, NULL, 1, MEM_CGROUP_ID_MAX, GFP_KERNEL); - if (memcg->id.id < 0) + if (memcg->id.id < 0) { + error = memcg->id.id; goto fail; + } memcg->vmstats_local = alloc_percpu(struct memcg_vmstats_percpu); if (!memcg->vmstats_local) @@ -5158,7 +5161,7 @@ static struct mem_cgroup *mem_cgroup_all fail: mem_cgroup_id_remove(memcg); __mem_cgroup_free(memcg); - return NULL; + return ERR_PTR(error); } static struct cgroup_subsys_state * __ref @@ -5169,8 +5172,8 @@ mem_cgroup_css_alloc(struct cgroup_subsy long error = -ENOMEM; memcg = mem_cgroup_alloc(); - if (!memcg) - return ERR_PTR(error); + if (IS_ERR(memcg)) + return ERR_CAST(memcg); memcg->high = PAGE_COUNTER_MAX; memcg->soft_limit = PAGE_COUNTER_MAX; @@ -5220,7 +5223,7 @@ mem_cgroup_css_alloc(struct cgroup_subsy fail: mem_cgroup_id_remove(memcg); mem_cgroup_free(memcg); - return ERR_PTR(-ENOMEM); + return ERR_PTR(error); } static int mem_cgroup_css_online(struct cgroup_subsys_state *css)