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=-5.3 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable 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 A85BDC432C3 for ; Sat, 23 Nov 2019 17:35:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 85A482068D for ; Sat, 23 Nov 2019 17:35:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1574530551; bh=dKzEpKOOSPW3aZELtJVwMo8eAbxh/xiZ2r+45+IxQBg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=ArapJrYJb3yTTPew5U4/Kdm+HQdUuWWojy8pOSrNV8hdfwsC7q3K6vYhHkAskV5hU p4HOXIi4pxfPXLjEm5RML1j8vk68GQwZJGCgjAL6I1KMNR7YRC47LTwNQaAlrSObR6 4RN8i3uCZfi9q6s3hyO68T+/AiwU1/kicV/jugS4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726740AbfKWRfu (ORCPT ); Sat, 23 Nov 2019 12:35:50 -0500 Received: from mail.kernel.org ([198.145.29.99]:33174 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726494AbfKWRfu (ORCPT ); Sat, 23 Nov 2019 12:35:50 -0500 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id D627B2067D; Sat, 23 Nov 2019 17:35:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1574530549; bh=dKzEpKOOSPW3aZELtJVwMo8eAbxh/xiZ2r+45+IxQBg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=bT/gRgearKafLLp9ZCRBcTuKU0mAOHE/B+YL1MQaI2E4F3BLv+dWIOu4CLkcrHcrZ C0u+P8/oscSnnR6TAmnzup69DHKHQBC238UR8CphPjOMQ5Qv8UhISP3suI1wc0qtSv o4xo+S95gNZZKIp6Twqj5cbIHAPV9fg76DEXbUD8= Date: Sat, 23 Nov 2019 18:35:47 +0100 From: Greg Kroah-Hartman To: Matthew Wilcox Cc: Guenter Roeck , linux-kernel@vger.kernel.org, torvalds@linux-foundation.org, akpm@linux-foundation.org, shuah@kernel.org, patches@kernelci.org, ben.hutchings@codethink.co.uk, lkft-triage@lists.linaro.org, stable@vger.kernel.org Subject: Re: [PATCH 4.19 000/220] 4.19.86-stable review Message-ID: <20191123173547.GA2188842@kroah.com> References: <20191122100912.732983531@linuxfoundation.org> <20191122151631.GA2083451@kroah.com> <20191122170534.GV20752@bombadil.infradead.org> <20191122213331.GA2102330@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191122213331.GA2102330@kroah.com> User-Agent: Mutt/1.12.2 (2019-09-21) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Nov 22, 2019 at 10:33:31PM +0100, Greg Kroah-Hartman wrote: > On Fri, Nov 22, 2019 at 09:05:34AM -0800, Matthew Wilcox wrote: > > On Fri, Nov 22, 2019 at 04:16:31PM +0100, Greg Kroah-Hartman wrote: > > > On Fri, Nov 22, 2019 at 06:47:05AM -0800, Guenter Roeck wrote: > > > > On 11/22/19 2:26 AM, Greg Kroah-Hartman wrote: > > > > > This is the start of the stable review cycle for the 4.19.86 release. > > > > > There are 220 patches in this series, all will be posted as a response > > > > > to this one. If anyone has any issues with these being applied, please > > > > > let me know. > > > > > > > > > > Responses should be made by Sun, 24 Nov 2019 09:59:19 +0000. > > > > > Anything received after that time might be too late. > > > > > > > > > > > > > I see the following warning (at least for arm64, ppc64, and x86_64). > > > > This seems to be caused by "idr: Fix idr_get_next race with idr_remove". > > > > v4.14.y is also affected. Mainline and v5.3.y are not affected. > > > > That makes sense; the code in question is different after 4.19. > > Thanks for the report; it's very clear. > > > > > Willy, this looks like something from your patch, is it to be expected? > > > > It's harmless; the problem is that we can't check whether the dereference > > is safe. The caller isn't holding the RCU lock, and the IDR code doesn't > > know what lock is being held to make this dereference safe. Do you want > > a changelog for this oneliner which disables the checking? > > > > diff --git a/lib/idr.c b/lib/idr.c > > index 49e7918603c7..6ff3b1c36e0a 100644 > > --- a/lib/idr.c > > +++ b/lib/idr.c > > @@ -237,7 +237,7 @@ void *idr_get_next(struct idr *idr, int *nextid) > > > > id = (id < base) ? 0 : id - base; > > radix_tree_for_each_slot(slot, &idr->idr_rt, &iter, id) { > > - entry = radix_tree_deref_slot(slot); > > + entry = rcu_dereference_raw(*slot); > > if (!entry) > > continue; > > if (!radix_tree_deref_retry(entry)) > > Thanks for this, I'll merge it with the existing patch tomorrow, it's > late here... Now fixed up in the 4.14 and 4.19 trees, thanks. greg k-h