From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752956AbcGTIB5 (ORCPT ); Wed, 20 Jul 2016 04:01:57 -0400 Received: from hqemgate14.nvidia.com ([216.228.121.143]:16694 "EHLO hqemgate14.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752492AbcGTIB4 (ORCPT ); Wed, 20 Jul 2016 04:01:56 -0400 X-PGP-Universal: processed; by hqnvupgp08.nvidia.com on Wed, 20 Jul 2016 00:59:35 -0700 From: Jim Lin To: CC: , , , Jim Lin Subject: [PATCH 1/1] usb: xhci: Fix panic if disconnect Date: Wed, 20 Jul 2016 16:01:41 +0800 Message-ID: <1469001701-5666-1-git-send-email-jilin@nvidia.com> X-Mailer: git-send-email 1.9.1 X-NVConfidentiality: public MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org After a device is disconnected, xhci_stop_device() will be invoked in xhci_bus_suspend(). Also the "disconnect" IRQ will have ISR to invoke xhci_free_virt_device() in this sequence. xhci_irq -> xhci_handle_event -> handle_cmd_completion -> xhci_handle_cmd_disable_slot -> xhci_free_virt_device If xhci->devs[slot_id] has been assigned to NULL in xhci_free_virt_device(), then virt_dev->eps[i].ring in xhci_stop_device() may point to an invlid address to cause kernel panic. virt_dev = xhci->devs[slot_id]; : if (virt_dev->eps[i].ring && virt_dev->eps[i].ring->dequeue) [] Unable to handle kernel paging request at virtual address 00001a68 [] pgd=ffffffc001430000 [] [00001a68] *pgd=000000013c807003, *pud=000000013c807003, *pmd=000000013c808003, *pte=0000000000000000 [] Internal error: Oops: 96000006 [#1] PREEMPT SMP [] CPU: 0 PID: 39 Comm: kworker/0:1 Tainted: G U [] Workqueue: pm pm_runtime_work [] task: ffffffc0bc0e0bc0 ti: ffffffc0bc0ec000 task.ti: ffffffc0bc0ec000 [] PC is at xhci_stop_device.constprop.11+0xb4/0x1a4 This issue is found when running with realtek ethernet device (0bda:8153). Signed-off-by: Jim Lin --- drivers/usb/host/xhci-hub.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/usb/host/xhci-hub.c b/drivers/usb/host/xhci-hub.c index d61fcc4..730b9fd 100644 --- a/drivers/usb/host/xhci-hub.c +++ b/drivers/usb/host/xhci-hub.c @@ -386,6 +386,9 @@ static int xhci_stop_device(struct xhci_hcd *xhci, int slot_id, int suspend) ret = 0; virt_dev = xhci->devs[slot_id]; + if (!virt_dev) + return -ENODEV; + cmd = xhci_alloc_command(xhci, false, true, GFP_NOIO); if (!cmd) { xhci_dbg(xhci, "Couldn't allocate command structure.\n"); -- 1.9.1