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=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=ham 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 628A1CA90AF for ; Tue, 12 May 2020 19:20:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 48086206A5 for ; Tue, 12 May 2020 19:20:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728039AbgELTUo convert rfc822-to-8bit (ORCPT ); Tue, 12 May 2020 15:20:44 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:48070 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725554AbgELTUo (ORCPT ); Tue, 12 May 2020 15:20:44 -0400 Received: from 1.general.jvosburgh.us.vpn ([10.172.68.206] helo=famine.localdomain) by youngberry.canonical.com with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.86_2) (envelope-from ) id 1jYaS8-0002XR-Ms; Tue, 12 May 2020 19:20:33 +0000 Received: by famine.localdomain (Postfix, from userid 1000) id ED86367BB3; Tue, 12 May 2020 12:20:30 -0700 (PDT) Received: from famine (localhost [127.0.0.1]) by famine.localdomain (Postfix) with ESMTP id E8090AC1DB; Tue, 12 May 2020 12:20:30 -0700 (PDT) From: Jay Vosburgh To: sathyanarayanan.kuppuswamy@linux.intel.com cc: bhelgaas@google.com, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, ashok.raj@intel.com, Yicong Yang , liudongdong 00290354 , Linuxarm Subject: Re: [PATCH v1 1/1] PCI/ERR: Handle fatal error recovery for non-hotplug capable devices In-reply-to: References: <18609.1588812972@famine> Comments: In-reply-to sathyanarayanan.kuppuswamy@linux.intel.com message dated "Wed, 06 May 2020 20:32:59 -0700." X-Mailer: MH-E 8.6+git; nmh 1.6; GNU Emacs 27.0.50 MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-ID: <9907.1589311230.1@famine> Content-Transfer-Encoding: 8BIT Date: Tue, 12 May 2020 12:20:30 -0700 Message-ID: <9908.1589311230@famine> Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org sathyanarayanan.kuppuswamy@linux.intel.com wrote: >From: Kuppuswamy Sathyanarayanan > >If there are non-hotplug capable devices connected to a given >port, then during the fatal error recovery(triggered by DPC or >AER), after calling reset_link() function, we cannot rely on >hotplug handler to detach and re-enumerate the device drivers >in the affected bus. Instead, we will have to let the error >recovery handler call report_slot_reset() for all devices in >the bus to notify about the reset operation. Although this is >only required for non hot-plug capable devices, doing it for >hotplug capable devices should not affect the functionality. Yicong, Does the patch below also resolve the issue for you, as with your changed version of my original patch? -J >Along with above issue, this fix also applicable to following >issue. > >Commit 6d2c89441571 ("PCI/ERR: Update error status after >reset_link()") added support to store status of reset_link() >call. Although this fixed the error recovery issue observed if >the initial value of error status is PCI_ERS_RESULT_DISCONNECT >or PCI_ERS_RESULT_NO_AER_DRIVER, it also discarded the status >result from report_frozen_detected. This can cause a failure to >recover if _NEED_RESET is returned by report_frozen_detected and >report_slot_reset is not invoked. > >Such an event can be induced for testing purposes by reducing the >Max_Payload_Size of a PCIe bridge to less than that of a device >downstream from the bridge, and then initiating I/O through the >device, resulting in oversize transactions. In the presence of DPC, >this results in a containment event and attempted reset and recovery >via pcie_do_recovery. After 6d2c89441571 report_slot_reset is not >invoked, and the device does not recover. > >[original patch is from jay.vosburgh@canonical.com] >[original patch link https://lore.kernel.org/linux-pci/18609.1588812972@famine/] >Fixes: 6d2c89441571 ("PCI/ERR: Update error status after reset_link()") >Signed-off-by: Jay Vosburgh >Signed-off-by: Kuppuswamy Sathyanarayanan >--- > drivers/pci/pcie/err.c | 19 +++++++++++++++---- > 1 file changed, 15 insertions(+), 4 deletions(-) > >diff --git a/drivers/pci/pcie/err.c b/drivers/pci/pcie/err.c >index 14bb8f54723e..db80e1ecb2dc 100644 >--- a/drivers/pci/pcie/err.c >+++ b/drivers/pci/pcie/err.c >@@ -165,13 +165,24 @@ pci_ers_result_t pcie_do_recovery(struct pci_dev *dev, > pci_dbg(dev, "broadcast error_detected message\n"); > if (state == pci_channel_io_frozen) { > pci_walk_bus(bus, report_frozen_detected, &status); >- status = reset_link(dev); >- if (status != PCI_ERS_RESULT_RECOVERED) { >+ status = PCI_ERS_RESULT_NEED_RESET; >+ } else { >+ pci_walk_bus(bus, report_normal_detected, &status); >+ } >+ >+ if (status == PCI_ERS_RESULT_NEED_RESET) { >+ if (reset_link) { >+ if (reset_link(dev) != PCI_ERS_RESULT_RECOVERED) >+ status = PCI_ERS_RESULT_DISCONNECT; >+ } else { >+ if (pci_bus_error_reset(dev)) >+ status = PCI_ERS_RESULT_DISCONNECT; >+ } >+ >+ if (status == PCI_ERS_RESULT_DISCONNECT) { > pci_warn(dev, "link reset failed\n"); > goto failed; > } >- } else { >- pci_walk_bus(bus, report_normal_detected, &status); > } > > if (status == PCI_ERS_RESULT_CAN_RECOVER) { >-- >2.17.1 > --- -Jay Vosburgh, jay.vosburgh@canonical.com