From patchwork Tue Aug 25 07:00:50 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Frank Heimes X-Patchwork-Id: 1350837 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (no SPF record) smtp.mailfrom=lists.ubuntu.com (client-ip=91.189.94.19; helo=huckleberry.canonical.com; envelope-from=kernel-team-bounces@lists.ubuntu.com; receiver=) Authentication-Results: ozlabs.org; dmarc=fail (p=none dis=none) header.from=canonical.com Received: from huckleberry.canonical.com (huckleberry.canonical.com [91.189.94.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 4BbKf54n9Mz9sTm; Tue, 25 Aug 2020 17:01:17 +1000 (AEST) Received: from localhost ([127.0.0.1] helo=huckleberry.canonical.com) by huckleberry.canonical.com with esmtp (Exim 4.86_2) (envelope-from ) id 1kASxG-0000ZA-R8; Tue, 25 Aug 2020 07:01:14 +0000 Received: from youngberry.canonical.com ([91.189.89.112]) by huckleberry.canonical.com with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.86_2) (envelope-from ) id 1kASxE-0000Yv-RX for kernel-team@lists.ubuntu.com; Tue, 25 Aug 2020 07:01:12 +0000 Received: from 2.general.fheimes.uk.vpn ([10.172.194.67] helo=T570.fritz.box) by youngberry.canonical.com with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.86_2) (envelope-from ) id 1kASxE-0007Yy-IO for kernel-team@lists.ubuntu.com; Tue, 25 Aug 2020 07:01:12 +0000 From: frank.heimes@canonical.com To: kernel-team@lists.ubuntu.com Subject: [SRU][F][PATCH 1/1] s390/pci: fix enabling a reserved PCI function Date: Tue, 25 Aug 2020 09:00:50 +0200 Message-Id: <20200825070050.752663-2-frank.heimes@canonical.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200825070050.752663-1-frank.heimes@canonical.com> References: <20200825070050.752663-1-frank.heimes@canonical.com> MIME-Version: 1.0 X-BeenThere: kernel-team@lists.ubuntu.com X-Mailman-Version: 2.1.20 Precedence: list List-Id: Kernel team discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: kernel-team-bounces@lists.ubuntu.com Sender: "kernel-team" From: Niklas Schnelle BugLink: https://bugs.launchpad.net/bugs/1891437 In usual IPL or hot plug scenarios a zPCI function transitions directly from reserved (invisible to Linux) to configured state or is configured by Linux itself using an SCLP, however it can also first go from reserved to standby and then from standby to configured without Linux initiative. In this scenario we first get a PEC event 0x302 and then 0x301. This may happen for example when the device is deconfigured at another LPAR and made available for this LPAR. It may also happen under z/VM when a device is attached while in some inconsistent state. However when we get the 0x301 the device is already known to zPCI so calling zpci_create() will add it twice resulting in the below BUG. Instead we should only enable the existing device and finally scan it through the PCI subsystem. list_add double add: new=00000000ed5a9008, prev=00000000ed5a9008, next=0000000083502300. kernel BUG at lib/list_debug.c:31! Krnl PSW : 0704c00180000000 0000000082dc2db8 (__list_add_valid+0x70/0xa8) Call Trace: [<0000000082dc2db8>] __list_add_valid+0x70/0xa8 ([<0000000082dc2db4>] __list_add_valid+0x6c/0xa8) [<00000000828ea920>] zpci_create_device+0x60/0x1b0 [<00000000828ef04a>] zpci_event_availability+0x282/0x2f0 [<000000008315f848>] chsc_process_crw+0x2b8/0xa18 [<000000008316735c>] crw_collect_info+0x254/0x348 [<00000000829226ea>] kthread+0x14a/0x168 [<000000008319d5c0>] ret_from_fork+0x24/0x2c Fixes: f606b3ef47c9 ("s390/pci: adapt events for zbus") Reported-by: Alexander Egorenkov Tested-by: Alexander Egorenkov Signed-off-by: Niklas Schnelle Signed-off-by: Heiko Carstens (cherry picked from commit 3047766bc6ec9c6bc9ece85b45a41ff401e8d988) Signed-off-by: Frank Heimes Acked-by: Stefan Bader Acked-by: Kleber Sacilotto de Souza --- arch/s390/pci/pci_event.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) diff --git a/arch/s390/pci/pci_event.c b/arch/s390/pci/pci_event.c index 08e1d619398e..fdebd286f402 100644 --- a/arch/s390/pci/pci_event.c +++ b/arch/s390/pci/pci_event.c @@ -94,7 +94,18 @@ static void __zpci_event_availability(struct zpci_ccdf_avail *ccdf) } zdev->fh = ccdf->fh; zdev->state = ZPCI_FN_STATE_CONFIGURED; - zpci_create_device(zdev); + ret = zpci_enable_device(zdev); + if (ret) + break; + + pdev = pci_scan_single_device(zdev->zbus->bus, zdev->devfn); + if (!pdev) + break; + + pci_bus_add_device(pdev); + pci_lock_rescan_remove(); + pci_bus_add_devices(zdev->zbus->bus); + pci_unlock_rescan_remove(); break; case 0x0302: /* Reserved -> Standby */ if (!zdev) {