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=-15.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 7BC4AC433E0 for ; Wed, 24 Feb 2021 20:07:09 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 0AE4A64EC3 for ; Wed, 24 Feb 2021 20:07:08 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0AE4A64EC3 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 885378D0021; Wed, 24 Feb 2021 15:07:08 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 80C568D001E; Wed, 24 Feb 2021 15:07:08 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 6D4CD8D0021; Wed, 24 Feb 2021 15:07:08 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0246.hostedemail.com [216.40.44.246]) by kanga.kvack.org (Postfix) with ESMTP id 53D378D001E for ; Wed, 24 Feb 2021 15:07:08 -0500 (EST) Received: from smtpin08.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 1EAFB185044C3 for ; Wed, 24 Feb 2021 20:07:08 +0000 (UTC) X-FDA: 77854245336.08.D2974F1 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf03.hostedemail.com (Postfix) with ESMTP id 9AE71C0007C9 for ; Wed, 24 Feb 2021 20:07:04 +0000 (UTC) Received: by mail.kernel.org (Postfix) with ESMTPSA id 4B16764E60; Wed, 24 Feb 2021 20:07:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1614197226; bh=U1XGcjm1zL4VDArObARHXrQYuQHUmmj/NdRZmLmtHbA=; h=Date:From:To:Subject:In-Reply-To:From; b=MWk1jijJ/85bjsjdSUeR0RYLYUpw9Gu06BeEbQHI94ruVpkkPSszUEzfSAIL+7tKv zanTGZBk0+w2SFhcrNBXrFIP61wxNfwxSG81jeA98L57yOX8R5kXMzuSt9RfbKpDsF wGo4W8AqQuiUBb00wy4WZhjwYfQNx+pAKbkbWxEw= Date: Wed, 24 Feb 2021 12:07:05 -0800 From: Andrew Morton To: akpm@linux-foundation.org, linmiaohe@huawei.com, linux-mm@kvack.org, louhongxiang@huawei.com, mike.kravetz@oracle.com, mm-commits@vger.kernel.org, torvalds@linux-foundation.org Subject: [patch 117/173] mm/hugetlb: fix use after free when subpool max_hpages accounting is not enabled Message-ID: <20210224200705.o8J0hqp8s%akpm@linux-foundation.org> In-Reply-To: <20210224115824.1e289a6895087f10c41dd8d6@linux-foundation.org> User-Agent: s-nail v14.8.16 X-Stat-Signature: t7gpuwy8msc5hrczmhzz86yrwmiayjzp X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 9AE71C0007C9 Received-SPF: none (linux-foundation.org>: No applicable sender policy available) receiver=imf03; identity=mailfrom; envelope-from=""; helo=mail.kernel.org; client-ip=198.145.29.99 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1614197224-76173 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: Miaohe Lin Subject: mm/hugetlb: fix use after free when subpool max_hpages accounting is not enabled If a hugetlbfs filesystem is created with the min_size option and without the size option, used_hpages is always 0 and might lead to release subpool prematurely because it indicates no pages are used now while there might be. In order to fix this issue, we should check used_hpages == 0 iff max_hpages accounting is enabled. As max_hpages accounting should be enabled in most common case, this is not worth a Cc stable. [mike.kravetz@oracle.com: new changelog] Link: https://lkml.kernel.org/r/20210126115510.53374-1-linmiaohe@huawei.com Signed-off-by: Hongxiang Lou Signed-off-by: Miaohe Lin Reviewed-by: Mike Kravetz Signed-off-by: Andrew Morton --- mm/hugetlb.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) --- a/mm/hugetlb.c~mm-hugetlb-fix-use-after-free-when-subpool-max_hpages-accounting-is-not-enabled +++ a/mm/hugetlb.c @@ -97,16 +97,26 @@ static inline void ClearPageHugeFreed(st /* Forward declaration */ static int hugetlb_acct_memory(struct hstate *h, long delta); -static inline void unlock_or_release_subpool(struct hugepage_subpool *spool) +static inline bool subpool_is_free(struct hugepage_subpool *spool) { - bool free = (spool->count == 0) && (spool->used_hpages == 0); + if (spool->count) + return false; + if (spool->max_hpages != -1) + return spool->used_hpages == 0; + if (spool->min_hpages != -1) + return spool->rsv_hpages == spool->min_hpages; + + return true; +} +static inline void unlock_or_release_subpool(struct hugepage_subpool *spool) +{ spin_unlock(&spool->lock); /* If no pages are used, and no other handles to the subpool * remain, give up any reservations based on minimum size and * free the subpool */ - if (free) { + if (subpool_is_free(spool)) { if (spool->min_hpages != -1) hugetlb_acct_memory(spool->hstate, -spool->min_hpages); _