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=-2.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 A6577C34026 for ; Tue, 18 Feb 2020 15:21:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 70D2121D56 for ; Tue, 18 Feb 2020 15:21:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582039298; bh=MsKV/xYN47aCVRgI/YrteenwxAkj4w1wnfbAF5aBSHs=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=q4a2RWzjMUrPuEuF5iG+6/Tqbo0YXcxu4g2vw/fc4tEUtsOhTzSsAXrO/+pOqI2of MUIOVvEf0rSqfsi5pBO6UukAd1Qy7e16gtVQnuwxO2PsL0mGyBfzeKxV8ZLN1uMsmI kjISvsUkQ74/sEKDqGx+3KlvkM6JOFmlQg2vBV4U= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726735AbgBRPVi (ORCPT ); Tue, 18 Feb 2020 10:21:38 -0500 Received: from mail.kernel.org ([198.145.29.99]:38866 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726721AbgBRPVh (ORCPT ); Tue, 18 Feb 2020 10:21:37 -0500 Received: from localhost (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (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 2712420679; Tue, 18 Feb 2020 15:21:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582039297; bh=MsKV/xYN47aCVRgI/YrteenwxAkj4w1wnfbAF5aBSHs=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Pb9iDQnqN+9vvY7eLj7gM0UgNTP9aNiFjDxf9K8iueuvqEbWn6IdR4EbZFucIF5zb YmDgBFhGnguj4EizvQqwwIkPN9QLsPgc4OC/L3qggqG1RNoR/14CLARUlSzAyfU6at o53F+ImSLaQACKxk44yoOHvSjxapsqBUhAylAwA0= Date: Tue, 18 Feb 2020 10:21:36 -0500 From: Sasha Levin To: Greg KH Cc: Santosh Sivaraj , stable@vger.kernel.org Subject: Re: Random memory corruption may occur due to incorrent tlb flushes Message-ID: <20200218152136.GL1734@sasha-vm> References: <87pnecxqlg.fsf@santosiv.in.ibm.com> <20200218084901.GA2285287@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: <20200218084901.GA2285287@kroah.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org On Tue, Feb 18, 2020 at 09:49:01AM +0100, Greg KH wrote: >On Tue, Feb 18, 2020 at 01:41:07PM +0530, Santosh Sivaraj wrote: >> Hi Greg/Sasha, >> >> The commit a46cc7a90fd (powerpc/mm/radix: Improve >> TLB/PWC flushes) picked up in 4.14 release has the potential to cause random >> memory corruption. This was fixed in 5.5 by the following patches. >> >> 12e4d53f3f powerpc/mmu_gather: enable RCU_TABLE_FREE even for !SMP case >> 0ed1325967 mm/mmu_gather: invalidate TLB correctly on batch allocation failure and flush >> 0758cd8304 asm-generic/tlb: avoid potential double flush >> >> It's a bit tricky to backport to 4.14 stable (though I have a backport to 4.19 >> stable, which I will post shortly). If you think it's important to fix this in >> 4.14, it would easier to revert the above mentioned commit (a46cc7a90fd). >> >> Please let me know your thoughts. > >A revert is probably best, can you send it? This is a bit tricky because a46cc7a90fd wasn't picked up by as, but rather is part of the 4.14 kernel. Please make sure you Cc the revert to the PowerPC mm folks so they could give it a careful review, as it's much more complex than just reverting a stable commit we queued up. -- Thanks, Sasha