From: Jim Lin Date: Tue, 16 Aug 2016 07:18:05 +0000 (+0300) Subject: usb: xhci: Fix panic if disconnect X-Git-Tag: v4.8-rc3~7^2~1 X-Git-Url: http://git.cascardo.eti.br/?p=cascardo%2Flinux.git;a=commitdiff_plain;h=88716a93766b8f095cdef37a8e8f2c93aa233b21 usb: xhci: Fix panic if disconnect 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 Cc: Signed-off-by: Mathias Nyman Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/usb/host/xhci-hub.c b/drivers/usb/host/xhci-hub.c index d61fcc48099e..730b9fd26685 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");