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 0008
pgd = ffc00165f000
[0008] *pgd=0174f003, *pud=0174f003,
*pmd=01750003, *pte=00e801751713
Internal error: Oops: 9605 [#1] PREEMPT SMP
Modules linked in: uinput uvcvideo videobuf2_vmalloc cmac [ ... ]
CPU: 5 PID: 3353 Comm: kworker/5:3 Tainted: GB 4.4.52 #480
Hardware name: Google Kevin (DT)
Workqueue: events driver_set_config_work
task: ffc0c369 ti: ffc0ae9a8000 task.ti: ffc0ae9a8000
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
---
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 f0dd08198d74..5286bf67869a 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -4275,7 +4275,7 @@ 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)
--
2.7.4
