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=-7.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 F1FC4C433E1 for ; Thu, 20 Aug 2020 13:29:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D11C120658 for ; Thu, 20 Aug 2020 13:29:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597930190; bh=TCYmLgf6ZeWa82TBbBiddjDcFsiYAq77Gs/NAYzu4RQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=NO17qH/As8GPvcLgAfVcuDPKJuE45nUw2/5pQ3ggvKTzxw7xH8ezU698Y9ZhPKmyG o18cSjJaPExYR0FliHRav2ra8z56B2r8DxHo4dgTN24V/y4Rhrt2sa3Jn+eikMXx+t bPpifrUKhgDtsAF/Cf7Y7DGBTQ2slnbw0pTpHDUQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729439AbgHTN3r (ORCPT ); Thu, 20 Aug 2020 09:29:47 -0400 Received: from mail.kernel.org ([198.145.29.99]:41536 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728770AbgHTN3Z (ORCPT ); Thu, 20 Aug 2020 09:29:25 -0400 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 0A631208A9; Thu, 20 Aug 2020 13:29:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597930165; bh=TCYmLgf6ZeWa82TBbBiddjDcFsiYAq77Gs/NAYzu4RQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=hSd2v8g7NzQcHTqpKc4MRnc3is4Z/W4nds9K2D9wx1uFlDRELkaHfG46pprMNl0qQ B/Ckq6ME9DSu0O226AGuDw79ue3YjbjiQnQ5vzcFuq4VdL+OTR45om/YxxdJaH06IQ wOUJjgMfT8Ezg6bZW8cSDDGylSNcvwwARkVRYacg= Date: Thu, 20 Aug 2020 09:29:24 -0400 From: Sasha Levin To: Michael Kelley Cc: Greg Kroah-Hartman , "linux-kernel@vger.kernel.org" , "stable@vger.kernel.org" , Wei Hu , Lorenzo Pieralisi Subject: Re: [PATCH 5.8 164/232] PCI: hv: Fix a timing issue which causes kdump to fail occasionally Message-ID: <20200820132924.GA8670@sasha-vm> References: <20200820091612.692383444@linuxfoundation.org> <20200820091620.754492308@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Aug 20, 2020 at 01:00:51PM +0000, Michael Kelley wrote: >From: Greg Kroah-Hartman Sent: Thursday, August 20, 2020 2:20 AM >> >> From: Wei Hu >> >> [ Upstream commit d6af2ed29c7c1c311b96dac989dcb991e90ee195 ] >> >> Kdump could fail sometime on Hyper-V guest because the retry in >> hv_pci_enter_d0() releases child device structures in hv_pci_bus_exit(). >> >> Although there is a second asynchronous device relations message sending >> from the host, if this message arrives to the guest after >> hv_send_resource_allocated() is called, the retry would fail. >> >> Fix the problem by moving retry to hv_pci_probe() and start the retry >> from hv_pci_query_relations() call. This will cause a device relations >> message to arrive to the guest synchronously; the guest would then be >> able to rebuild the child device structures before calling >> hv_send_resource_allocated(). >> >> Link: >> https://lore.kernel.org/linux-hyperv/20200727071731.18516-1-weh@microsoft.com/ >> Fixes: c81992e7f4aa ("PCI: hv: Retry PCI bus D0 entry on invalid device state") >> Signed-off-by: Wei Hu >> [lorenzo.pieralisi@arm.com: fixed a comment and commit log] >> Signed-off-by: Lorenzo Pieralisi >> Reviewed-by: Michael Kelley >> Signed-off-by: Sasha Levin >> --- >> drivers/pci/controller/pci-hyperv.c | 71 +++++++++++++++-------------- >> 1 file changed, 37 insertions(+), 34 deletions(-) >> > >This patch came through three days ago, and I indicated then that we don't want >it backported to 5.8 and earlier. Uh, I re-added it by mistake, sorry. -- Thanks, Sasha