From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751371AbcGGMMN (ORCPT ); Thu, 7 Jul 2016 08:12:13 -0400 Received: from szxga01-in.huawei.com ([58.251.152.64]:24747 "EHLO szxga01-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750922AbcGGMMG (ORCPT ); Thu, 7 Jul 2016 08:12:06 -0400 From: Zhen Lei To: Catalin Marinas , Will Deacon , linux-arm-kernel , linux-kernel CC: Zefan Li , Xinwei Hu , "Tianhong Ding" , Hanjun Guo , Zhen Lei Subject: [PATCH 1/1] arm64/hugetlb: clear PG_dcache_clean if the page is dirty when munmap Date: Thu, 7 Jul 2016 20:09:04 +0800 Message-ID: <1467893344-8352-1-git-send-email-thunder.leizhen@huawei.com> X-Mailer: git-send-email 1.9.5.msysgit.1 MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.177.23.164] X-CFilter-Loop: Reflected X-Mirapoint-Virus-RAPID-Raw: score=unknown(0), refid=str=0001.0A0B0206.577E4711.0029,ss=1,re=0.000,recu=0.000,reip=0.000,cl=1,cld=1,fgs=0, ip=0.0.0.0, so=2013-06-18 04:22:30, dmn=2013-03-21 17:37:32 X-Mirapoint-Loop-Id: 59c42e7c37e82fd024ab09013a0925d7 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org At present, PG_dcache_clean is only cleared when the related huge page is about to be freed. But sometimes, there maybe a process is in charge to copy binary codes into a shared memory, and notifies other processes to execute base on that. For the first time, there is no problem, because the default value of page->flags is PG_dcache_clean cleared. So the cache will be maintained at the time of set_pte_at for other processes. But if the content of the shared memory have been updated again, there is no cache operations, because the PG_dcache_clean is still set. For example: Process A open a hugetlbfs file mmap it as a shared memory copy some binary codes into it munmap Process B open the hugetlbfs file mmap it as a shared memory, executable invoke the functions in the shared memory munmap repeat the above steps. Signed-off-by: Zhen Lei --- arch/arm64/mm/hugetlbpage.c | 20 +++++++++++++++----- 1 file changed, 15 insertions(+), 5 deletions(-) diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c index 2e49bd2..547b158 100644 --- a/arch/arm64/mm/hugetlbpage.c +++ b/arch/arm64/mm/hugetlbpage.c @@ -201,6 +201,7 @@ pte_t huge_ptep_get_and_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep) { pte_t pte; + struct page *page; if (pte_cont(*ptep)) { int ncontig, i; @@ -222,12 +223,21 @@ pte_t huge_ptep_get_and_clear(struct mm_struct *mm, if (pte_dirty(ptep_get_and_clear(mm, addr, cpte))) is_dirty = true; } - if (is_dirty) - return pte_mkdirty(pte); - else - return pte; + if (is_dirty) { + pte = pte_mkdirty(pte); + page = pte_page(pte); + clear_bit(PG_dcache_clean, &page->flags); + } + + return pte; } else { - return ptep_get_and_clear(mm, addr, ptep); + pte = ptep_get_and_clear(mm, addr, ptep); + if (huge_pte_dirty(pte)) { + page = pte_page(pte); + clear_bit(PG_dcache_clean, &page->flags); + } + + return pte; } } -- 2.5.0