Path: csiph.com!1.us.feeder.erje.net!feeder.erje.net!2.eu.feeder.erje.net!newsfeed.datemas.de!weretis.net!feeder4.news.weretis.net!storethat.news.telefonica.de!telefonica.de!news.panservice.it!bofh.it!news.nic.it!robomod From: Yinghai Lu Newsgroups: linux.kernel Subject: [PATCH] PCI/aspm: Fix link->downstream setting Date: Wed, 01 Mar 2017 09:30:02 +0100 Message-ID: X-Mailer: git-send-email 2.8.3 X-Source-IP: aserv0022.oracle.com [141.146.126.234] Sender: robomod@news.nic.it List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Approved: robomod@news.nic.it Lines: 62 Organization: linux.* mail to news gateway X-Original-Cc: linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, Yinghai Lu X-Original-Date: Wed, 1 Mar 2017 00:25:40 -0800 X-Original-Message-ID: <20170301082540.23995-1-yinghai@kernel.org> X-Original-Sender: linux-kernel-owner@vger.kernel.org Xref: csiph.com linux.kernel:1590089 ~ # 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