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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B72EEC433EF for ; Sat, 13 Nov 2021 15:44:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 810C461039 for ; Sat, 13 Nov 2021 15:44:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235946AbhKMPrh (ORCPT ); Sat, 13 Nov 2021 10:47:37 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36438 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231880AbhKMPrg (ORCPT ); Sat, 13 Nov 2021 10:47:36 -0500 Received: from mail-pf1-x429.google.com (mail-pf1-x429.google.com [IPv6:2607:f8b0:4864:20::429]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5DCBBC061766 for ; Sat, 13 Nov 2021 07:44:44 -0800 (PST) Received: by mail-pf1-x429.google.com with SMTP id n85so11045974pfd.10 for ; Sat, 13 Nov 2021 07:44:44 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=CiFvkxkml/E3hXlk6viC87ZsHB//A7EeJApdZ7JR+24=; b=AhBqsrkR6Fp1PCg8xJzMWdHyQh6BMpzd1VQXjD7eq24JgAEh/aQLmilgvbgj9Lvtl7 1a4y44tdB/zCNR9YJU0t+Y6UiTsUqrn/lZGt+Jl5Xa5JtsB+ExkAPaYJxaPPpz2V35yG uZwtUM7QRU7apJtAZIRfNBpAWt7Oj2kjBnFjLMTRP2IDipBUh7IAQsWZz447GOckgsxp ybzBFRKIRXvJS5FC87J8VL1kCiLk4l8q78MS0GDqFDaJDfK7cVPG3INWdmG+8uXwt/fd mBVcB2mOfhgYKoY+RnlQGPA7MqcfgLypx6gdjK+L5wnHmVJbvvVgPLwtHTfdbUssqi3L oo7g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=CiFvkxkml/E3hXlk6viC87ZsHB//A7EeJApdZ7JR+24=; b=i8bI3Bqg1Y2B9jXuZmC9vTqO45ewi7xEdHsFs1Y4FbWC2JQnKU+CxvzrXnnOUQsyug zAXby2lr0NrMSGD4FrWqoTHD9SmGyV3yj1cJxLsvAIkj/sgywIEKqOkn4Gy1I7oflobk uAootRAaSxz70+WXsNiBfeJcqMAxdbmJ1a+flbWaxHJ/eresMYHE2kqfR8oMT2N/JvYu +cYnT1CnZpAaNo+e5w2Tg9E4CKeh6uxL49taieL8+lRkftPdlrboMPVqwcTdEFoCANlv XbEHPl0rFPMCciFsv+FE2gEuUhYz/6aUZNf8hPYFHP+0WlV06ENu00NS04fGb/oaImuZ C3ow== X-Gm-Message-State: AOAM531bl4YQj1Wfqr2lBNdMHpIn4Sx0BhQE/6vQnZKfRUYc1KhobWHR CXoGFinwPDyABJOb9Or6qLE= X-Google-Smtp-Source: ABdhPJx1VOktTq/wTyazaQKuTgGuBrVRN5rl7mqgaWSQ9s7vhuM2ASOEpckNlz+ko7kRKquhceum/w== X-Received: by 2002:a62:6184:0:b0:4a2:a063:fe8e with SMTP id v126-20020a626184000000b004a2a063fe8emr2105905pfb.69.1636818283847; Sat, 13 Nov 2021 07:44:43 -0800 (PST) Received: from localhost.localdomain ([113.172.190.100]) by smtp.googlemail.com with ESMTPSA id q13sm10847651pfk.22.2021.11.13.07.44.41 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 13 Nov 2021 07:44:43 -0800 (PST) From: Bui Quang Minh Cc: Bui Quang Minh , Mike Kravetz , Andrew Morton , Miaohe Lin , Michal Hocko , Muchun Song , Mina Almasry , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: [PATCH] hugetlb: fix hugetlb cgroup refcounting during mremap Date: Sat, 13 Nov 2021 22:44:10 +0700 Message-Id: <20211113154412.91134-1-minhquangbui99@gmail.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit To: unlisted-recipients:; (no To-header on input) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When hugetlb_vm_op_open() is called during copy_vma(), we may take the reference to resv_map->css. Later, when clearing the reservation pointer of old_vma after transferring it to new_vma, we forget to drop the reference to resv_map->css. This leads to a reference leak of css. Fixes this by adding a check to drop reservation css reference in clear_vma_resv_huge_pages() Fixes: 550a7d6 (mm, hugepages: add mremap() support for hugepage backed vma) Signed-off-by: Bui Quang Minh --- include/linux/hugetlb_cgroup.h | 12 ++++++++++++ mm/hugetlb.c | 4 +++- 2 files changed, 15 insertions(+), 1 deletion(-) diff --git a/include/linux/hugetlb_cgroup.h b/include/linux/hugetlb_cgroup.h index c137396129db..ba025ae27882 100644 --- a/include/linux/hugetlb_cgroup.h +++ b/include/linux/hugetlb_cgroup.h @@ -128,6 +128,13 @@ static inline void resv_map_dup_hugetlb_cgroup_uncharge_info( css_get(resv_map->css); } +static inline void resv_map_put_hugetlb_cgroup_uncharge_info( + struct resv_map *resv_map) +{ + if (resv_map->css) + css_put(resv_map->css); +} + extern int hugetlb_cgroup_charge_cgroup(int idx, unsigned long nr_pages, struct hugetlb_cgroup **ptr); extern int hugetlb_cgroup_charge_cgroup_rsvd(int idx, unsigned long nr_pages, @@ -211,6 +218,11 @@ static inline void resv_map_dup_hugetlb_cgroup_uncharge_info( { } +static inline void resv_map_put_hugetlb_cgroup_uncharge_info( + struct resv_map *resv_map) +{ +} + static inline int hugetlb_cgroup_charge_cgroup(int idx, unsigned long nr_pages, struct hugetlb_cgroup **ptr) { diff --git a/mm/hugetlb.c b/mm/hugetlb.c index e09159c957e3..3a2479003ddf 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -1037,8 +1037,10 @@ void clear_vma_resv_huge_pages(struct vm_area_struct *vma) */ struct resv_map *reservations = vma_resv_map(vma); - if (reservations && is_vma_resv_set(vma, HPAGE_RESV_OWNER)) + if (reservations && is_vma_resv_set(vma, HPAGE_RESV_OWNER)) { + resv_map_put_hugetlb_cgroup_uncharge_info(reservations); kref_put(&reservations->refs, resv_map_release); + } reset_vma_resv_huge_pages(vma); } -- 2.25.1