On Fri, Dec 01, 2017 at 06:38:16AM -0800, Guenter Roeck wrote: > On Fri, Dec 1, 2017 at 3:41 AM, Mathias Nyman > <mathias.nyman@xxxxxxxxxxxxxxx> wrote: > > From: Yu Chen <chenyu56@xxxxxxxxxx> > > > > Check vdev->real_port 0 to avoid panic > > [ 9.261347] [<ffffff800884a390>] xhci_free_virt_devices_depth_first+0x58/0x108 > > [ 9.261352] [<ffffff800884a814>] xhci_mem_cleanup+0x1bc/0x570 > > [ 9.261355] [<ffffff8008842de8>] xhci_stop+0x140/0x1c8 > > [ 9.261365] [<ffffff80087ed304>] usb_remove_hcd+0xfc/0x1d0 > > [ 9.261369] [<ffffff80088551c4>] xhci_plat_remove+0x6c/0xa8 > > [ 9.261377] [<ffffff80086e928c>] platform_drv_remove+0x2c/0x70 > > [ 9.261384] [<ffffff80086e6ea0>] __device_release_driver+0x80/0x108 > > [ 9.261387] [<ffffff80086e7a1c>] device_release_driver+0x2c/0x40 > > [ 9.261392] [<ffffff80086e5f28>] bus_remove_device+0xe0/0x120 > > [ 9.261396] [<ffffff80086e2e34>] device_del+0x114/0x210 > > [ 9.261399] [<ffffff80086e9e00>] platform_device_del+0x30/0xa0 > > [ 9.261403] [<ffffff8008810bdc>] dwc3_otg_work+0x204/0x488 > > [ 9.261407] [<ffffff80088133fc>] event_work+0x304/0x5b8 > > [ 9.261414] [<ffffff80080e31b0>] process_one_work+0x148/0x490 > > [ 9.261417] [<ffffff80080e3548>] worker_thread+0x50/0x4a0 > > [ 9.261421] [<ffffff80080e9ea0>] kthread+0xe8/0x100 > > [ 9.261427] [<ffffff8008083680>] ret_from_fork+0x10/0x50 > > > > The problem can occur if xhci_plat_remove() is called shortly after > > xhci_plat_probe(). While xhci_free_virt_devices_depth_first been > > called before the device has been setup and get real_port initialized. > > The problem occurred on Hikey960 and was reproduced by Guenter Roeck > > on Kevin with chromeos-4.4. > > > > Cc: Guenter Roeck <groeck@xxxxxxxxxx> > > Cc: <stable@xxxxxxxxxxxxxxx> # v4.10+ > > Fixes: ee8665e28e8d ("xhci: free xhci virtual devices with leaf nodes first") > > would probably be better. That patch is in v4.4.y as well as in > v4.9.y, and thus both releases are affected. I've added this fixes line, thanks. greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html