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=-3.9 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 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 37D86C2D0A3 for ; Mon, 9 Nov 2020 10:19:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AD47F206B2 for ; Mon, 9 Nov 2020 10:19:07 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=kroah.com header.i=@kroah.com header.b="nOKRFt2i"; dkim=temperror (0-bit key) header.d=messagingengine.com header.i=@messagingengine.com header.b="PHUniTN9" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726535AbgKIKTH (ORCPT ); Mon, 9 Nov 2020 05:19:07 -0500 Received: from wout1-smtp.messagingengine.com ([64.147.123.24]:57201 "EHLO wout1-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726176AbgKIKTH (ORCPT ); Mon, 9 Nov 2020 05:19:07 -0500 Received: from compute4.internal (compute4.nyi.internal [10.202.2.44]) by mailout.west.internal (Postfix) with ESMTP id 4AE0A127B; Mon, 9 Nov 2020 05:19:06 -0500 (EST) Received: from mailfrontend2 ([10.202.2.163]) by compute4.internal (MEProxy); Mon, 09 Nov 2020 05:19:06 -0500 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=fm2; bh=s/qsySht1lZ9NDOoV5qxwwNqljC MtNT8sJkdgyDqpU4=; b=nOKRFt2ihnXqA240lHgtGQLLS9wsBTtqtFiRawERqWX v8egPNV85IQB4nyHZejIk2ZOoIn8TWP0CFeZe6X9r8oGutCZyFZeKvrzBTGJgpsy VQ4s6k2/oMXOOvc1tTP5pOZPJFNxVnE6hHGXmZzz89o6jK8ealGBFyKxxwwY8L7V 6kA4waMO+0l6VVMExvhM6k4Hx5Alatf/bhL07OJc2h7eSvlaTxaKhAS7ef5ZE6t5 ddAXdC53se+IfRNeY7ri/IRj+APktn6vkyqvNsbK+Omba//kfRvn3c8CV3MsEbmS RAzfk/2mt0fhspKp2Uir1ioVss1JX1u0VQDRUzd8BuQ== 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=fm1; bh=s/qsyS ht1lZ9NDOoV5qxwwNqljCMtNT8sJkdgyDqpU4=; b=PHUniTN97f8DHxgTeSlpys i89jOBBx2/4PsQCntcE/ulbjr7lbXrfLMMSVojfGqHQ0dg3e4rxPSHuOq61C1mBr HAjbYW7x/elyFrqEG1GHCtnZ7nFkGn5Il0xHk5KkBQeJaClWtVpg8um9C8bvNK+e MfRc2FlPGoTfQynz+BQqvlTCdqz3mx5/SkKcjOSiICz/dx+JOrObZwdN3lUNNL/H uaeOaKk25Kc2HgZI9qCQ9bX7qNLw07rNkvAJiLEslKC2kx6XR5u5t5qeE24BDuUi 2p9bWPJgPbT2J8fG6OI7clS+3a+5e+GLAYFfzhkil1LACb7hcg0ow2u6+yU/S1sQ == X-ME-Sender: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgedujedrudduhedgudehucetufdoteggodetrfdotf fvucfrrhhofhhilhgvmecuhfgrshhtofgrihhlpdfqfgfvpdfurfetoffkrfgpnffqhgen uceurghilhhouhhtmecufedttdenucesvcftvggtihhpihgvnhhtshculddquddttddmne cujfgurhepfffhvffukfhfgggtuggjsehttdertddttddvnecuhfhrohhmpefirhgvghcu mffjuceoghhrvghgsehkrhhorghhrdgtohhmqeenucggtffrrghtthgvrhhnpeevueehje fgfffgiedvudekvdektdelleelgefhleejieeugeegveeuuddukedvteenucfkphepkeef rdekiedrjeegrdeigeenucevlhhushhtvghrufhiiigvpedtnecurfgrrhgrmhepmhgrih hlfhhrohhmpehgrhgvgheskhhrohgrhhdrtghomh X-ME-Proxy: Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) by mail.messagingengine.com (Postfix) with ESMTPA id 416123063082; Mon, 9 Nov 2020 05:19:05 -0500 (EST) Date: Mon, 9 Nov 2020 11:20:06 +0100 From: Greg KH To: Linus Torvalds Cc: stable , Oleg Nesterov Subject: Re: [PATCH] fork: fix copy_process(CLONE_PARENT) race with the exiting ->real_parent Message-ID: <20201109102006.GA1238384@kroah.com> References: <20201107064722.GA139215@arch-e3.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org On Sun, Nov 08, 2020 at 11:56:48AM -0800, Linus Torvalds wrote: > .. oh, and I suspect it should have been marked for stable. > > I added Oleg's ack (implicit in an earlier thread), but didn't add a stable tag. > > It's commit b4e00444cab4 ("fork: fix copy_process(CLONE_PARENT) race > with the exiting ->real_parent") in my tree. > > I'm not sure how serious it is. Yeah, the race can cause the wrong > exit signal in theory, but I think you almost have to do it with > cooperating processes, at which point you could have just done it > intentionally in the first place. > > But it does look like a real data race, and the fix looks small and > obvious enough that I think it's stable material. Now queued up to stable trees, thanks! greg k-h