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 750B6C433FE for ; Mon, 10 Oct 2022 19:07:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229761AbiJJTHW (ORCPT ); Mon, 10 Oct 2022 15:07:22 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41510 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229697AbiJJTHV (ORCPT ); Mon, 10 Oct 2022 15:07:21 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A08791ADB7 for ; Mon, 10 Oct 2022 12:07:20 -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 5A4FF60EF9 for ; Mon, 10 Oct 2022 19:07:19 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6C0B1C433C1; Mon, 10 Oct 2022 19:07:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1665428838; bh=9+vd2DCu/VJwmEGPuVhwnwfGI/Bgenh05yFjvLX/VsM=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Sii25ggXsgS/Pp9XwnuicchkWvVPLFfKfBhjVMiZYNiBen/lYuCjzQAXT7UlA6hle nFdp6/DRktzpPbhxO4vR1dXwYjIsWRplzPF+Z8huLDN/560wg/mgnOv2nmrGE8MQsG I0SWoMJBNlU2qaUgvwtp163uiwqsFe+nYPDr2EMw= Date: Mon, 10 Oct 2022 21:08:02 +0200 From: Greg KH To: Mikulas Patocka Cc: stable@vger.kernel.org Subject: Re: backport of patches 8238b4579866b7c1bb99883cfe102a43db5506ff and d6ffe6067a54972564552ea45d320fb98db1ac5e Message-ID: References: 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 Wed, Oct 05, 2022 at 06:48:54PM +0200, Greg KH wrote: > On Mon, Oct 03, 2022 at 08:28:06AM -0400, Mikulas Patocka wrote: > > > > > > On Sat, 1 Oct 2022, Greg KH wrote: > > > > > On Fri, Sep 30, 2022 at 11:32:30AM -0400, Mikulas Patocka wrote: > > > > Hi > > > > > > > > Here I'm submitting backport of patches > > > > 8238b4579866b7c1bb99883cfe102a43db5506ff and > > > > d6ffe6067a54972564552ea45d320fb98db1ac5e to the stable branches. > > > > > > Thanks, but you provide no information as to why these are needed. > > > > > > What needs them? They are just adding new functions to the tree from > > > what I can tell. > > > > > > thanks, > > > > > > greg k-h > > > > There's a race condition in wait_on_bit. wait_on_bit tests a bit using the > > "test_bit" function, however this function doesn't do any memory barrier, > > so the memory accesses that follow wait_on_bit may be reordered before it > > and return invalid data. > > > > Linus didn't want to add a memory barrier to wait_on_bit, he instead > > wanted to introduce a new function test_bit_acquire that performs the > > "acquire" memory barrier and use it in wait_on_bit. > > > > The patch d6ffe6067a54972564552ea45d320fb98db1ac5e fixes an oversight in > > the patch 8238b4579866b7c1bb99883cfe102a43db5506ff where the function > > test_bit_acquire was not defined for some architectures and this caused > > compile failure. > > > > The backport of the patch 8238b4579866b7c1bb99883cfe102a43db5506ff should > > be applied first and the backport of the patch > > d6ffe6067a54972564552ea45d320fb98db1ac5e afterwards. > > All now queued up, thanks. Nope, these cause loads of breakages. See https://lore.kernel.org/r/09eca44e-4d91-a060-d48c-d0aa41ac5045@roeck-us.net for one such example, and I know kbuild sent you other build problems. I'll drop all of these from the stable trees now. Please feel free to resend them when you have the build issues worked out. thanks, greg k-h