Chris Bainbridge ac1a97d8a5 usb: core: hub: hub_port_init lock controller instead of bus ... commit feb26ac31a upstream. The XHCI controller presents two USB buses to the system - one for USB2 and one for USB3. The hub init code (hub_port_init) is reentrant but only locks one bus per thread, leading to a race condition failure when two threads attempt to simultaneously initialise a USB2 and USB3 device: [ 8.034843] xhci_hcd 0000:00:14.0: Timeout while waiting for setup device command [ 13.183701] usb 3-3: device descriptor read/all, error -110 On a test system this failure occurred on 6% of all boots. The call traces at the point of failure are: Call Trace: [<ffffffff81b9bab7>] schedule+0x37/0x90 [<ffffffff817da7cd>] usb_kill_urb+0x8d/0xd0 [<ffffffff8111e5e0>] ? wake_up_atomic_t+0x30/0x30 [<ffffffff817dafbe>] usb_start_wait_urb+0xbe/0x150 [<ffffffff817db10c>] usb_control_msg+0xbc/0xf0 [<ffffffff817d07de>] hub_port_init+0x51e/0xb70 [<ffffffff817d4697>] hub_event+0x817/0x1570 [<ffffffff810f3e6f>] process_one_work+0x1ff/0x620 [<ffffffff810f3dcf>] ? process_one_work+0x15f/0x620 [<ffffffff810f4684>] worker_thread+0x64/0x4b0 [<ffffffff810f4620>] ? rescuer_thread+0x390/0x390 [<ffffffff810fa7f5>] kthread+0x105/0x120 [<ffffffff810fa6f0>] ? kthread_create_on_node+0x200/0x200 [<ffffffff81ba183f>] ret_from_fork+0x3f/0x70 [<ffffffff810fa6f0>] ? kthread_create_on_node+0x200/0x200 Call Trace: [<ffffffff817fd36d>] xhci_setup_device+0x53d/0xa40 [<ffffffff817fd87e>] xhci_address_device+0xe/0x10 [<ffffffff817d047f>] hub_port_init+0x1bf/0xb70 [<ffffffff811247ed>] ? trace_hardirqs_on+0xd/0x10 [<ffffffff817d4697>] hub_event+0x817/0x1570 [<ffffffff810f3e6f>] process_one_work+0x1ff/0x620 [<ffffffff810f3dcf>] ? process_one_work+0x15f/0x620 [<ffffffff810f4684>] worker_thread+0x64/0x4b0 [<ffffffff810f4620>] ? rescuer_thread+0x390/0x390 [<ffffffff810fa7f5>] kthread+0x105/0x120 [<ffffffff810fa6f0>] ? kthread_create_on_node+0x200/0x200 [<ffffffff81ba183f>] ret_from_fork+0x3f/0x70 [<ffffffff810fa6f0>] ? kthread_create_on_node+0x200/0x200 Which results from the two call chains: hub_port_init usb_get_device_descriptor usb_get_descriptor usb_control_msg usb_internal_control_msg usb_start_wait_urb usb_submit_urb / wait_for_completion_timeout / usb_kill_urb hub_port_init hub_set_address xhci_address_device xhci_setup_device Mathias Nyman explains the current behaviour violates the XHCI spec: hub_port_reset() will end up moving the corresponding xhci device slot to default state. As hub_port_reset() is called several times in hub_port_init() it sounds reasonable that we could end up with two threads having their xhci device slots in default state at the same time, which according to xhci 4.5.3 specs still is a big no no: "Note: Software shall not transition more than one Device Slot to the Default State at a time" So both threads fail at their next task after this. One fails to read the descriptor, and the other fails addressing the device. Fix this in hub_port_init by locking the USB controller (instead of an individual bus) to prevent simultaneous initialisation of both buses. Fixes: 638139eb95 ("usb: hub: allow to process more usb hub events in parallel") Link: https://lkml.org/lkml/2016/2/8/312 Link: https://lkml.org/lkml/2016/2/4/748 Signed-off-by: Chris Bainbridge <chris.bainbridge@gmail.com> Cc: stable <stable@vger.kernel.org> Acked-by: Mathias Nyman <mathias.nyman@linux.intel.com> Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org> [sumits: minor merge conflict resolution for linux-4.4.y] Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2017-03-26 12:13:16 +02:00
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association.h
atmel_usba_udc.h
audio-v2.h
audio.h
c67x00.h
cdc-wdm.h
cdc.h
cdc_ncm.h	net: cdc_ncm: avoid changing RX/TX buffers on MTU changes	2015-12-23 22:52:08 -05:00
ch9.h
chipidea.h
composite.h
ehci-dbgp.h
ehci_def.h	USB: EHCI: declare hostpc register as zero-length array	2016-07-27 09:47:28 -07:00
ehci_pdriver.h
ezusb.h
functionfs.h
g_hid.h
gadget.h
gadget_configfs.h
gpio_vbus.h
hcd.h	usb: core: hub: hub_port_init lock controller instead of bus	2017-03-26 12:13:16 +02:00
input.h
iowarrior.h
irda.h
isp116x.h
isp1301.h
isp1362.h
isp1760.h
m66592.h
msm_hsusb.h
msm_hsusb_hw.h
musb-omap.h
musb-ux500.h
musb.h
net2280.h
of.h
ohci_pdriver.h
otg-fsm.h
otg.h
phy.h
phy_companion.h
quirks.h	USB: add quirk for devices with broken LPM	2015-12-11 15:40:51 -08:00
r8a66597.h
renesas_usbhs.h
rndis_host.h
samsung_usb_phy.h
serial.h
sl811.h
storage.h
tegra_usb_phy.h
tilegx.h
uas.h
ulpi.h
usb338x.h
usb_phy_generic.h
usbnet.h
wusb-wa.h
wusb.h
xhci_pdriver.h