From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752053AbdCAI02 (ORCPT ); Wed, 1 Mar 2017 03:26:28 -0500 Received: from aserp1040.oracle.com ([141.146.126.69]:31230 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751902AbdCAI0P (ORCPT ); Wed, 1 Mar 2017 03:26:15 -0500 From: Yinghai Lu To: Bjorn Helgaas , Rajat Jain Cc: linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, Yinghai Lu Subject: [PATCH] PCI/aspm: Fix link->downstream setting Date: Wed, 1 Mar 2017 00:25:40 -0800 Message-Id: <20170301082540.23995-1-yinghai@kernel.org> X-Mailer: git-send-email 2.8.3 X-Source-IP: aserv0022.oracle.com [141.146.126.234] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org ~ # echo 1 > /sys/bus/pci/devices/0000\:0b\:00.0/remove ... BUG: unable to handle kernel NULL pointer dereference at 0000000000000080 IP: pcie_config_aspm_link+0x5d/0x2b0 Call Trace: pcie_aspm_exit_link_state+0x75/0x130 pci_stop_bus_device+0xa4/0xb0 pci_stop_and_remove_bus_device_locked+0x1a/0x30 remove_store+0x50/0x70 dev_attr_store+0x18/0x30 sysfs_kf_write+0x44/0x60 kernfs_fop_write+0x10e/0x190 __vfs_write+0x28/0x110 ? rcu_read_lock_sched_held+0x5d/0x80 ? rcu_sync_lockdep_assert+0x2c/0x60 ? __sb_start_write+0x173/0x1a0 ? vfs_write+0xb3/0x180 vfs_write+0xc4/0x180 SyS_write+0x49/0xa0 do_syscall_64+0xa6/0x1c0 entry_SYSCALL64_slow_path+0x25/0x25 ---[ end trace bd187ee0267df5d9 ]--- set downstream even with blacklist path. Signed-off-by: Yinghai Lu --- drivers/pci/pcie/aspm.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) Index: linux-2.6/drivers/pci/pcie/aspm.c =================================================================== --- linux-2.6.orig/drivers/pci/pcie/aspm.c +++ linux-2.6/drivers/pci/pcie/aspm.c @@ -478,7 +478,7 @@ static void aspm_calc_l1ss_info(struct p static void pcie_aspm_cap_init(struct pcie_link_state *link, int blacklist) { - struct pci_dev *child, *parent = link->pdev; + struct pci_dev *child = link->downstream, *parent = link->pdev; struct pci_bus *linkbus = parent->subordinate; struct aspm_register_info upreg, dwreg; @@ -491,9 +491,7 @@ static void pcie_aspm_cap_init(struct pc /* Get upstream/downstream components' register state */ pcie_get_aspm_reg(parent, &upreg); - child = pci_function_0(linkbus); pcie_get_aspm_reg(child, &dwreg); - link->downstream = child; /* * If ASPM not supported, don't mess with the clocks and link, @@ -800,6 +798,7 @@ static struct pcie_link_state *alloc_pci INIT_LIST_HEAD(&link->children); INIT_LIST_HEAD(&link->link); link->pdev = pdev; + link->downstream = pci_function_0(pdev->subordinate); /* * Root Ports and PCI/PCI-X to PCIe Bridges are roots of PCIe