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[23.128.96.18]) by mx.google.com with ESMTP id p16si4317128ilc.75.2021.09.16.17.55.27; Thu, 16 Sep 2021 17:55:41 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; dkim=pass header.i=@linuxfoundation.org header.s=korg header.b=t2ZSR+j5; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=linuxfoundation.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344747AbhIPRFP (ORCPT + 99 others); Thu, 16 Sep 2021 13:05:15 -0400 Received: from mail.kernel.org ([198.145.29.99]:34146 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1348106AbhIPRBs (ORCPT ); Thu, 16 Sep 2021 13:01:48 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 11F8461AEF; Thu, 16 Sep 2021 16:33:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1631809994; bh=x1llO8I6QY/aU77mY1he9oAnkTsjZPkxu0kn8jqQHcY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=t2ZSR+j50bNLtEcvQ9i6ofWGYRvl0tKEZUjg5t13g+CFD8KY+TzPaNWSgb9Wws45g cMdPkGjf3S98w/pT9VL8BUXcgbxakdd3CesUQJLxNr/I5FZQyuBX8z52LOqHjHbhaI MOAbd9JLvrbhVxqDtkDtpgMreF6sEHkLQRaDRnxM= 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 5.13 360/380] mm/hugetlb: initialize hugetlb_usage in mm_init Date: Thu, 16 Sep 2021 18:01:57 +0200 Message-Id: <20210916155816.306888747@linuxfoundation.org> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20210916155803.966362085@linuxfoundation.org> References: <20210916155803.966362085@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 @@ -835,6 +835,11 @@ 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); @@ -1019,6 +1024,10 @@ 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 @@ -1045,6 +1045,7 @@ 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;