From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf1-f198.google.com (mail-pf1-f198.google.com [209.85.210.198]) by kanga.kvack.org (Postfix) with ESMTP id 454D06B4CDE for ; Wed, 28 Nov 2018 07:14:37 -0500 (EST) Received: by mail-pf1-f198.google.com with SMTP id d6-v6so16675711pfn.19 for ; Wed, 28 Nov 2018 04:14:37 -0800 (PST) Received: from out30-132.freemail.mail.aliyun.com (out30-132.freemail.mail.aliyun.com. [115.124.30.132]) by mx.google.com with ESMTPS id x9si7113437pge.76.2018.11.28.04.14.34 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 28 Nov 2018 04:14:35 -0800 (PST) Subject: Re: [PATCH 008/216] x86, pageattr: Prevent overflow in slow_virt_to_phys() for X86_PAE References: <1543404768-89470-1-git-send-email-alex.shi@linux.alibaba.com> <1543404768-89470-8-git-send-email-alex.shi@linux.alibaba.com> From: Alex Shi Message-ID: <1573cbad-29cd-f34e-a005-1a6906a4cd4e@linux.alibaba.com> Date: Wed, 28 Nov 2018 20:14:21 +0800 MIME-Version: 1.0 In-Reply-To: <1543404768-89470-8-git-send-email-alex.shi@linux.alibaba.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Content-Language: en-US Sender: owner-linux-mm@kvack.org List-ID: To: Yang Shi , Michael Wang , Xunlei Pang Cc: Dexuan Cui , "K. Y. Srinivasan" , Haiyang Zhang , gregkh@linuxfoundation.org, linux-mm@kvack.org, olaf@aepfle.de, apw@canonical.com, jasowang@redhat.com, dave.hansen@intel.com, riel@redhat.com, stable@vger.kernel.org, Thomas Gleixner Hi, All, Please ignore this stupid email thread. I thought I had suppressed cc in gitconfig. But I am wrong... Very very sorry! Thanks Alex On 2018/11/28 7:29 PM, Alex Shi wrote: > From: Dexuan Cui > > commit d1cd1210834649ce1ca6bafe5ac25d2f40331343 upstream. > > pte_pfn() returns a PFN of long (32 bits in 32-PAE), so "long << > PAGE_SHIFT" will overflow for PFNs above 4GB. > > Due to this issue, some Linux 32-PAE distros, running as guests on Hyper-V, > with 5GB memory assigned, can't load the netvsc driver successfully and > hence the synthetic network device can't work (we can use the kernel parameter > mem=3000M to work around the issue). > > Cast pte_pfn() to phys_addr_t before shifting. > > Fixes: "commit d76565344512: x86, mm: Create slow_virt_to_phys()" > Signed-off-by: Dexuan Cui > Cc: K. Y. Srinivasan > Cc: Haiyang Zhang > Cc: gregkh@linuxfoundation.org > Cc: linux-mm@kvack.org > Cc: olaf@aepfle.de > Cc: apw@canonical.com > Cc: jasowang@redhat.com > Cc: dave.hansen@intel.com > Cc: riel@redhat.com > Cc: stable@vger.kernel.org > Link: http://lkml.kernel.org/r/1414580017-27444-1-git-send-email-decui@microsoft.com > Signed-off-by: Thomas Gleixner > Signed-off-by: Greg Kroah-Hartman > Signed-off-by: Alex Shi > --- > 7u/arch/x86/mm/pageattr.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/7u/arch/x86/mm/pageattr.c b/7u/arch/x86/mm/pageattr.c > index 4ed2b2d..81b82f4 100644 > --- a/7u/arch/x86/mm/pageattr.c > +++ b/7u/arch/x86/mm/pageattr.c > @@ -405,7 +405,7 @@ phys_addr_t slow_virt_to_phys(void *__virt_addr) > psize = page_level_size(level); > pmask = page_level_mask(level); > offset = virt_addr & ~pmask; > - phys_addr = pte_pfn(*pte) << PAGE_SHIFT; > + phys_addr = (phys_addr_t)pte_pfn(*pte) << PAGE_SHIFT; > return (phys_addr | offset); > } > EXPORT_SYMBOL_GPL(slow_virt_to_phys);