From patchwork Tue Aug 15 15:19:11 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ding Tianhong X-Patchwork-Id: 9902073 X-Patchwork-Delegate: bhelgaas@google.com Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 49FA6602C9 for ; Tue, 15 Aug 2017 15:25:36 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 3C7CE28882 for ; Tue, 15 Aug 2017 15:25:36 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 3133328897; Tue, 15 Aug 2017 15:25:36 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id AC40728882 for ; Tue, 15 Aug 2017 15:25:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752219AbdHOPZe (ORCPT ); Tue, 15 Aug 2017 11:25:34 -0400 Received: from szxga05-in.huawei.com ([45.249.212.191]:3542 "EHLO szxga05-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751949AbdHOPZd (ORCPT ); Tue, 15 Aug 2017 11:25:33 -0400 Received: from 172.30.72.59 (EHLO DGGEMS410-HUB.china.huawei.com) ([172.30.72.59]) by dggrg05-dlp.huawei.com (MOS 4.4.6-GA FastPath queued) with ESMTP id DFH21831; Tue, 15 Aug 2017 23:25:11 +0800 (CST) Received: from localhost (10.177.23.32) by DGGEMS410-HUB.china.huawei.com (10.3.19.210) with Microsoft SMTP Server id 14.3.301.0; Tue, 15 Aug 2017 23:25:01 +0800 From: Ding Tianhong To: , , , , , , , , , , , , , , , , , , , , , , , , , CC: Ding Tianhong , Eric Dumazet Subject: [PATCH net] pci: fix oops when try to find Root Port for a PCI device Date: Tue, 15 Aug 2017 23:19:11 +0800 Message-ID: <1502810351-8312-1-git-send-email-dingtianhong@huawei.com> X-Mailer: git-send-email 1.8.5.2.msysgit.0 MIME-Version: 1.0 X-Originating-IP: [10.177.23.32] X-CFilter-Loop: Reflected X-Mirapoint-Virus-RAPID-Raw: score=unknown(0), refid=str=0001.0A020201.59931259.012E, ss=1, re=0.000, recu=0.000, reip=0.000, cl=1, cld=1, fgs=0, ip=0.0.0.0, so=2014-11-16 11:51:01, dmn=2013-03-21 17:37:32 X-Mirapoint-Loop-Id: a17a72501644fba6802aa8d2edf0b7a2 Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Eric report a oops when booting the system after applying the commit a99b646afa8a ("PCI: Disable PCIe Relaxed..."): [ 4.241029] BUG: unable to handle kernel NULL pointer dereference at 0000000000000050 [ 4.247001] IP: pci_find_pcie_root_port+0x62/0x80 [ 4.253011] PGD 0 [ 4.253011] P4D 0 [ 4.253011] [ 4.258013] Oops: 0000 [#1] SMP DEBUG_PAGEALLOC [ 4.262015] Modules linked in: [ 4.265005] CPU: 31 PID: 1 Comm: swapper/0 Not tainted 4.13.0-dbx-DEV #316 [ 4.271002] Hardware name: Intel RML,PCH/Iota_QC_19, BIOS 2.40.0 06/22/2016 [ 4.279002] task: ffffa2ee38cfa040 task.stack: ffffa51ec0004000 [ 4.285001] RIP: 0010:pci_find_pcie_root_port+0x62/0x80 [ 4.290012] RSP: 0000:ffffa51ec0007ab8 EFLAGS: 00010246 [ 4.295003] RAX: 0000000000000000 RBX: ffffa2ee36bae000 RCX: 0000000000000006 [ 4.303002] RDX: 000000000000081c RSI: ffffa2ee38cfa8c8 RDI: ffffa2ee36bae000 [ 4.310013] RBP: ffffa51ec0007b58 R08: 0000000000000001 R09: 0000000000000000 [ 4.317001] R10: 0000000000000000 R11: 0000000000000000 R12: ffffa51ec0007ad0 [ 4.324005] R13: ffffa2ee36bae098 R14: 0000000000000002 R15: ffffa2ee37204818 [ 4.331002] FS: 0000000000000000(0000) GS:ffffa2ee3fcc0000(0000) knlGS:0000000000000000 [ 4.339002] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 4.345001] CR2: 0000000000000050 CR3: 000000401000f000 CR4: 00000000001406e0 [ 4.351002] Call Trace: [ 4.354012] ? pci_configure_device+0x19f/0x570 [ 4.359002] ? pci_conf1_read+0xb8/0xf0 [ 4.363002] ? raw_pci_read+0x23/0x40 [ 4.366011] ? pci_read+0x2c/0x30 [ 4.370014] ? pci_read_config_word+0x67/0x70 [ 4.374012] pci_device_add+0x28/0x230 [ 4.378012] ? pci_vpd_f0_read+0x50/0x80 [ 4.382014] pci_scan_single_device+0x96/0xc0 [ 4.386012] pci_scan_slot+0x79/0xf0 [ 4.389001] pci_scan_child_bus+0x31/0x180 [ 4.394014] acpi_pci_root_create+0x1c6/0x240 [ 4.398013] pci_acpi_scan_root+0x15f/0x1b0 [ 4.402012] acpi_pci_root_add+0x2e6/0x400 [ 4.406012] ? acpi_evaluate_integer+0x37/0x60 [ 4.411002] acpi_bus_attach+0xdf/0x200 [ 4.415002] acpi_bus_attach+0x6a/0x200 [ 4.418014] acpi_bus_attach+0x6a/0x200 [ 4.422013] acpi_bus_scan+0x38/0x70 [ 4.426011] acpi_scan_init+0x10c/0x271 [ 4.429001] acpi_init+0x2fa/0x348 [ 4.433004] ? acpi_sleep_proc_init+0x2d/0x2d [ 4.437001] do_one_initcall+0x43/0x169 [ 4.441001] kernel_init_freeable+0x1d0/0x258 [ 4.445003] ? rest_init+0xe0/0xe0 [ 4.449001] kernel_init+0xe/0x150 ====================== cut here ============================= It looks like the pci_find_pcie_root_port() was trying to find the Root Port for the PCI device which is the Root Port already, it will return NULL and trigger the problem, so check the highest_pcie_bridge to fix thie problem. Fixes: a99b646afa8a ("PCI: Disable PCIe Relaxed Ordering if unsupported") Reported-by: Eric Dumazet Signed-off-by: Eric Dumazet Signed-off-by: Ding Tianhong --- drivers/pci/pci.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index af0cc34..7e2022f 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -522,7 +522,8 @@ struct pci_dev *pci_find_pcie_root_port(struct pci_dev *dev) bridge = pci_upstream_bridge(bridge); } - if (pci_pcie_type(highest_pcie_bridge) != PCI_EXP_TYPE_ROOT_PORT) + if (highest_pcie_bridge && + pci_pcie_type(highest_pcie_bridge) != PCI_EXP_TYPE_ROOT_PORT) return NULL; return highest_pcie_bridge;