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=-20.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, 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 9CEB6C433F5 for ; Mon, 20 Sep 2021 18:01:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 866D8610A8 for ; Mon, 20 Sep 2021 18:01:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1357164AbhITSDI (ORCPT ); Mon, 20 Sep 2021 14:03:08 -0400 Received: from mail.kernel.org ([198.145.29.99]:54560 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1355741AbhITR4d (ORCPT ); Mon, 20 Sep 2021 13:56:33 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 0D0FE63156; Mon, 20 Sep 2021 17:14:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1632158062; bh=K/KDn5XN9ILhtKfOVWsqrXgoFClZtPwe1tuyUK9bwE8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=2Mrz5gMeOVBk6DT7d0rC/IXE1n2fM6H9lgYmqWvx9wMLbk0s4HyFwKuQpx4cbVSOP P19sbAOXhFBAPkcqsq367nmcrV0Q8633IOqeoTeZPmAYR0BnlBoYKnw6zacFfR09xA pt9RJFRADx/lYmFurwJ3QJlW4Q8lZcGdyLLgmVrk= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Liu Zixian , Naoya Horiguchi , Mike Kravetz , Andrew Morton , Linus Torvalds Subject: [PATCH 4.19 246/293] mm/hugetlb: initialize hugetlb_usage in mm_init Date: Mon, 20 Sep 2021 18:43:28 +0200 Message-Id: <20210920163941.812970901@linuxfoundation.org> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20210920163933.258815435@linuxfoundation.org> References: <20210920163933.258815435@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Liu Zixian commit 13db8c50477d83ad3e3b9b0ae247e5cd833a7ae4 upstream. After fork, the child process will get incorrect (2x) hugetlb_usage. If a process uses 5 2MB hugetlb pages in an anonymous mapping, HugetlbPages: 10240 kB and then forks, the child will show, HugetlbPages: 20480 kB The reason for double the amount is because hugetlb_usage will be copied from the parent and then increased when we copy page tables from parent to child. Child will have 2x actual usage. Fix this by adding hugetlb_count_init in mm_init. Link: https://lkml.kernel.org/r/20210826071742.877-1-liuzixian4@huawei.com Fixes: 5d317b2b6536 ("mm: hugetlb: proc: add HugetlbPages field to /proc/PID/status") Signed-off-by: Liu Zixian Reviewed-by: Naoya Horiguchi Reviewed-by: Mike Kravetz Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- include/linux/hugetlb.h | 9 +++++++++ kernel/fork.c | 1 + 2 files changed, 10 insertions(+) --- a/include/linux/hugetlb.h +++ b/include/linux/hugetlb.h @@ -513,6 +513,11 @@ static inline spinlock_t *huge_pte_lockp void hugetlb_report_usage(struct seq_file *m, struct mm_struct *mm); +static inline void hugetlb_count_init(struct mm_struct *mm) +{ + atomic_long_set(&mm->hugetlb_usage, 0); +} + static inline void hugetlb_count_add(long l, struct mm_struct *mm) { atomic_long_add(l, &mm->hugetlb_usage); @@ -593,6 +598,10 @@ static inline spinlock_t *huge_pte_lockp return &mm->page_table_lock; } +static inline void hugetlb_count_init(struct mm_struct *mm) +{ +} + static inline void hugetlb_report_usage(struct seq_file *f, struct mm_struct *m) { } --- a/kernel/fork.c +++ b/kernel/fork.c @@ -964,6 +964,7 @@ static struct mm_struct *mm_init(struct mm->pmd_huge_pte = NULL; #endif mm_init_uprobes_state(mm); + hugetlb_count_init(mm); if (current->mm) { mm->flags = current->mm->flags & MMF_INIT_MASK;