From 14a2032287d43bbffadf22752e40830000aad503 Mon Sep 17 00:00:00 2001 From: Guenter Roeck Date: Wed, 8 Mar 2017 10:19:36 -0800 Subject: [PATCH] usb: hub: Fix crash after failure to read BOS descriptor commit 7b2db29fbb4e766fcd02207eb2e2087170bd6ebc upstream. If usb_get_bos_descriptor() returns an error, usb->bos will be NULL. Nevertheless, it is dereferenced unconditionally in hub_set_initial_usb2_lpm_policy() if usb2_hw_lpm_capable is set. This results in a crash. usb 5-1: unable to get BOS descriptor ... Unable to handle kernel NULL pointer dereference at virtual address 00000008 pgd = ffffffc00165f000 [00000008] *pgd=000000000174f003, *pud=000000000174f003, *pmd=0000000001750003, *pte=00e8000001751713 Internal error: Oops: 96000005 [#1] PREEMPT SMP Modules linked in: uinput uvcvideo videobuf2_vmalloc cmac [ ... ] CPU: 5 PID: 3353 Comm: kworker/5:3 Tainted: G B 4.4.52 #480 Hardware name: Google Kevin (DT) Workqueue: events driver_set_config_work task: ffffffc0c3690000 ti: ffffffc0ae9a8000 task.ti: ffffffc0ae9a8000 PC is at hub_port_init+0xc3c/0xd10 LR is at hub_port_init+0xc3c/0xd10 ... Call trace: [] hub_port_init+0xc3c/0xd10 [] usb_reset_and_verify_device+0x15c/0x82c [] usb_reset_device+0xe4/0x298 [] rtl8152_probe+0x84/0x9b0 [r8152] [] usb_probe_interface+0x244/0x2f8 [] driver_probe_device+0x180/0x3b4 [] __device_attach_driver+0xb4/0xe0 [] bus_for_each_drv+0xb4/0xe4 [] __device_attach+0xd0/0x158 [] device_initial_probe+0x24/0x30 [] bus_probe_device+0x50/0xe4 [] device_add+0x414/0x738 [] usb_set_configuration+0x89c/0x914 [] driver_set_config_work+0xc0/0xf0 [] process_one_work+0x390/0x6b8 [] worker_thread+0x480/0x610 [] kthread+0x164/0x178 [] ret_from_fork+0x10/0x40 Since we don't know anything about LPM capabilities without BOS descriptor, don't attempt to enable LPM if it is not available. Fixes: 890dae886721 ("xhci: Enable LPM support only for hardwired ...") Cc: Mathias Nyman Signed-off-by: Guenter Roeck Acked-by: Mathias Nyman Signed-off-by: Greg Kroah-Hartman --- drivers/usb/core/hub.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c index f52d8abf6979..9e62c93af96e 100644 --- a/drivers/usb/core/hub.c +++ b/drivers/usb/core/hub.c @@ -4199,7 +4199,7 @@ static void hub_set_initial_usb2_lpm_policy(struct usb_device *udev) struct usb_hub *hub = usb_hub_to_struct_hub(udev->parent); int connect_type = USB_PORT_CONNECT_TYPE_UNKNOWN; - if (!udev->usb2_hw_lpm_capable) + if (!udev->usb2_hw_lpm_capable || !udev->bos) return; if (hub) -- 2.20.1