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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id BC77CC433EF for ; Mon, 25 Apr 2022 23:34:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235669AbiDYXho (ORCPT ); Mon, 25 Apr 2022 19:37:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51574 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231827AbiDYXhm (ORCPT ); Mon, 25 Apr 2022 19:37:42 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 39E6489CC2 for ; Mon, 25 Apr 2022 16:34:37 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id C4DB361570 for ; Mon, 25 Apr 2022 23:34:36 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C5DB8C385A4; Mon, 25 Apr 2022 23:34:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1650929676; bh=Eb05Em8JyGymAnY18gau+jnazmwGgMGqqJHMO8BcqEA=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=mDZAIzTbhfrTVINNUPKfY3iFdNiym/TmrJK94cBioGkuUjv6wwjvUSb1gNy5Y8eQk xZ07TFcINLWAe8jbTzAjwgLE9MHOQKbczWol+deAepUCLMLdV1cBKtccb79shkG91/ ROexynsf2fwPoqxl108PqlQ7E6blmB/OuOPCwaiQ= Date: Mon, 25 Apr 2022 16:34:34 -0700 From: Andrew Morton To: Luis Chamberlain Cc: kernel test robot , Julius Hemanth Pitti , Johannes Weiner , Kees Cook , Iurii Zaikin , Ingo Molnar , Al Viro , LKML , lkp@lists.01.org, lkp@intel.com, Eli Cohen Subject: Re: [proc/sysctl] 1dd38979b2: BUG:kernel_NULL_pointer_dereference,address Message-Id: <20220425163434.5f8f47e8c301ea30c2f94a5a@linux-foundation.org> In-Reply-To: References: <20220425083302.GD21864@xsang-OptiPlex-9020> <20220425144607.2c2588e6b1f00ab8a6f3f6ea@linux-foundation.org> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.33; x86_64-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 25 Apr 2022 16:08:57 -0700 Luis Chamberlain wrote: > On Mon, Apr 25, 2022 at 02:46:07PM -0700, Andrew Morton wrote: > > On Mon, 25 Apr 2022 12:00:21 -0700 Luis Chamberlain wrote: > > > > > Andrew, can we drop this patch for now? > > > > I've been sitting on (ie, forgotten about) this patch > > (https://lore.kernel.org/all/20200709235115.56954-1-jpitti@cisco.com/T/#u) > > Jesh, yeah I see. > > > for two years. Evidently waiting for you/Kees/Ingo to provide > > guidance. So sure, the need seems very unurgent so I can drop it. > > Well Keew as OK with it, but I yeah I can't decipher the issue at this > point in time. > > > However I fail to see how that patch could have caused this crash. I'm > > suspecting a bisection error? > > > > Maybe something is unwell in drivers/vdpa/vdpa_user/vduse_dev.c. > > At a quick glance, yes it could very well by vduse_init() is messy and > races somehow with init, but if a race does lurk here my instincts tell > me this can't be the only place. > > Not sure if leaving a patch in place more time to see how else things > can explode is worth it. Confused. Are you thinking that the above-linked patch was somehow involved in this crash? If so, but how? All it does it to permit unprivileged reads to four ints via proc_dointvec_minmax()?