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Fri, 16 Feb 2018 12:43:25 -0500 Received: from userp2120.oracle.com ([156.151.31.85]:39322 "EHLO userp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751115AbeBPRnZ (ORCPT ); Fri, 16 Feb 2018 12:43:25 -0500 Subject: Re: [PATCH] mm: don't defer struct page initialization for Xen pv guests To: Juergen Gross , Michal Hocko Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, xen-devel@lists.xenproject.org, akpm@linux-foundation.org, stable@vger.kernel.org References: <20180216133726.30813-1-jgross@suse.com> <20180216135940.GQ7275@dhcp22.suse.cz> <1424bb25-7d6a-ee21-83b4-0e90369d6132@suse.com> From: Pavel Tatashin Message-ID: Date: Fri, 16 Feb 2018 09:21:57 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.6.0 MIME-Version: 1.0 In-Reply-To: <1424bb25-7d6a-ee21-83b4-0e90369d6132@suse.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=8807 signatures=668673 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=890 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1711220000 definitions=main-1802160211 Sender: stable-owner@vger.kernel.org X-Mailing-List: stable@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-Mailing-List: linux-kernel@vger.kernel.org List-ID: On 02/16/2018 09:02 AM, Juergen Gross wrote: > On 16/02/18 14:59, Michal Hocko wrote: >> [CC Pavel] >> >> On Fri 16-02-18 14:37:26, Juergen Gross wrote: >>> Commit f7f99100d8d95dbcf09e0216a143211e79418b9f ("mm: stop zeroing >>> memory during allocation in vmemmap") broke Xen pv domains in some >>> configurations, as the "Pinned" information in struct page of early >>> page tables could get lost. >> >> Could you be more specific please? > > In which way? Do you want to see the resulting crash in the commit > message or some more background information? Hi Juergen, Could you please provide details how to reproduce the problem, and crash message. Also, information about where exactly xen access struct pages before deferred pages are initialized. Thank you, Pasha > >> >>> Avoid this problem by not deferring struct page initialization when >>> running as Xen pv guest. >>> >>> Cc: #4.15 >> Fixes: f7f99100d8d9 ("mm: stop zeroing memory during allocation in vmemmap") >> >> please > > Okay. > > > Juergen >