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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no 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 CD09DC63798 for ; Thu, 22 Jul 2021 14:02:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AF3B56128A for ; Thu, 22 Jul 2021 14:02:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232255AbhGVNWE (ORCPT ); Thu, 22 Jul 2021 09:22:04 -0400 Received: from wnew3-smtp.messagingengine.com ([64.147.123.17]:33557 "EHLO wnew3-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232177AbhGVNWA (ORCPT ); Thu, 22 Jul 2021 09:22:00 -0400 Received: from compute2.internal (compute2.nyi.internal [10.202.2.42]) by mailnew.west.internal (Postfix) with ESMTP id 7B83E2B00BA0; Thu, 22 Jul 2021 10:02:24 -0400 (EDT) Received: from mailfrontend1 ([10.202.2.162]) by compute2.internal (MEProxy); Thu, 22 Jul 2021 10:02:25 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kroah.com; h= date:from:to:cc:subject:message-id:references:mime-version :content-type:in-reply-to; s=fm1; bh=C6CbgvrWGhTSu1mJtUQtOVibztV iE1SUbR/gHueA4Ec=; b=cn/4EYJ/72loKaRLF/QhNBFjZ6M/iTZKsxYyiRNfmUW /bjTttv/sGLHT5WhCnB1cf1xLWBnq0v/76gYOSwvqVj0DOhCHrO7x5a1jYUXC0vi ZmPNispxN7PG7HQIA+zTy/9Gv1BW6S6p5zzkyZUGR2sTq8kYLpIwwzHdjQqcznte d3wnUPojh20p/rTNjnth2Ffyr5JOfxf2fCblYIfQ0s7mgwyDBCyNCCUtAfD/rUHN VpqrSf/zcOX86IjfVohj7kiz9WXVOrSqyed1v8jrvrpAIEESQmaQptHVD8SW1fuA EptwgfhFB9NMQYEx5PPPd9+HflXPMl+BtGUVooiVwIQ== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:content-type:date:from:in-reply-to :message-id:mime-version:references:subject:to:x-me-proxy :x-me-proxy:x-me-sender:x-me-sender:x-sasl-enc; s=fm3; bh=C6Cbgv rWGhTSu1mJtUQtOVibztViE1SUbR/gHueA4Ec=; b=JctVrWUEhlKVgRiSy8dNS3 sb9GpI2BSiBqqsmmzJpVg8sDzKFxF3YRBtMNpC1zgu7q+N1g6EtylLL8HehitVwg KxqpwpM5ZEf+tvJEGdEz04FyOzakg5AOAYW8bs7O+28BipdP9O9/J8dWdHYloD7D iORaCnlDKgfi9jST/I38U747CM83PxPAmhQxu3qO2ygWDtd000mRWyn211+MT30N s1JxxMry2ac6OKTqtYmmZtmO9ZAB3tmK+UlKDgkpPzkp6kN/QgYGfE+I4D9pl6sm X42TFVzHZZdVV53ebFyQMOBZolUpFWB3j7IAk5Y82mhNRtBHFcPY7UDgnX9sGSaw == X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgedvtddrfeeigdeilecutefuodetggdotefrodftvf curfhrohhfihhlvgemucfhrghsthforghilhdpqfgfvfdpuffrtefokffrpgfnqfghnecu uegrihhlohhuthemuceftddtnecusecvtfgvtghiphhivghnthhsucdlqddutddtmdenuc fjughrpeffhffvuffkfhggtggujgesthdtredttddtvdenucfhrhhomhepifhrvghgucfm jfcuoehgrhgvgheskhhrohgrhhdrtghomheqnecuggftrfgrthhtvghrnhepueelledthe ekleethfeludduvdfhffeuvdffudevgeehkeegieffveehgeeftefgnecuffhomhgrihhn pehkvghrnhgvlhdrohhrghenucevlhhushhtvghrufhiiigvpedtnecurfgrrhgrmhepmh grihhlfhhrohhmpehgrhgvgheskhhrohgrhhdrtghomh X-ME-Proxy: Received: by mail.messagingengine.com (Postfix) with ESMTPA; Thu, 22 Jul 2021 10:02:22 -0400 (EDT) Date: Thu, 22 Jul 2021 16:02:18 +0200 From: Greg KH To: Hugh Dickins Cc: Peter Xu , stable , linux-mm , linux-kernel , Axel Rasmussen , Andrew Morton , Hillf Danton , Igor Raits Subject: Re: [PATCH stable 5.13.y/5.12.y 0/2] mm/thp: Fix uffd-wp with fork(); crash on pmd migration entry on fork Message-ID: References: <796cbb7-5a1c-1ba0-dde5-479aba8224f2@google.com> <20210720155150.497148-1-peterx@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jul 20, 2021 at 01:32:19PM -0700, Hugh Dickins wrote: > On Tue, Jul 20, 2021 at 8:52 AM Peter Xu wrote: > > > > In summary: this series should be needed for 5.10/5.12/5.13. This is the > > 5.13.y/5.12.y backport of the series, and it should be able to be applied on > > both of the branches. Patch 1 is a dependency of patch 2, while patch 2 should > > be the real fix. > > > > This series should be able to fix a rare race that mentioned in thread: > > > > https://lore.kernel.org/linux-mm/796cbb7-5a1c-1ba0-dde5-479aba8224f2@google.com/ > > > > This fact wasn't discovered when the fix got proposed and merged, because the > > fix was originally about uffd-wp and its fork event. However it turns out that > > the problematic commit b569a1760782f3d is also causing crashing on fork() of > > pmd migration entries which is even more severe than the original uffd-wp > > problem. > > > > Stable kernels at least on 5.12.y has the crash reproduced, and it's possible > > 5.13.y and 5.10.y could hit it due to having the problematic commit > > b569a1760782f3d but lacking of the uffd-wp fix patch (8f34f1eac382, which is > > also patch 2 of this series). > > > > The pmd entry crash problem was reported by Igor Raits and > > debugged by Hugh Dickins . > > > > Please review, thanks. > > These two 5.13.y patches look just right to me, thank you Peter (and > 5.12.19 announced EOL overnight, so nothing more wanted for that). > > But these do just amount to asking stable@vger.kernel.org to > cherry-pick the two commits > 5fc7a5f6fd04bc18f309d9f979b32ef7d1d0a997 > 8f34f1eac3820fc2722e5159acceb22545b30b0d Thanks for the review, both now queued up to 5.13.y. greg k-h