usb: hub: Fix usb enumeration issue due to address0 race
commit 6ae6dc22d2d1ce6aa77a6da8a761e61aca216f8b upstream.
xHC hardware can only have one slot in default state with address 0
waiting for a unique address at a time, otherwise "undefined behavior
may occur" according to xhci spec 5.4.3.4
The address0_mutex exists to prevent this across both xhci roothubs.
If hub_port_init() fails, it may unlock the mutex and exit with a xhci
slot in default state. If the other xhci roothub calls hub_port_init()
at this point we end up with two slots in default state.
Make sure the address0_mutex protects the slot default state across
hub_port_init() retries, until slot is addressed or disabled.
Note, one known minor case is not fixed by this patch.
If device needs to be reset during resume, but fails all hub_port_init()
retries in usb_reset_and_verify_device(), then it's possible the slot is
still left in default state when address0_mutex is unlocked.
Cc: <stable@vger.kernel.org>
Fixes: 638139eb95d2 ("usb: hub: allow to process more usb hub events in parallel")
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20211115221630.871204-1-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 92057a3..c2bfac4 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -4460,8 +4460,6 @@
if (oldspeed == USB_SPEED_LOW)
delay = HUB_LONG_RESET_TIME;
- mutex_lock(hcd->address0_mutex);
-
/* Reset the device; full speed may morph to high speed */
/* FIXME a USB 2.0 device may morph into SuperSpeed on reset. */
retval = hub_port_reset(hub, port1, udev, delay, false);
@@ -4748,7 +4746,6 @@
hub_port_disable(hub, port1, 0);
update_devnum(udev, devnum); /* for disconnect processing */
}
- mutex_unlock(hcd->address0_mutex);
return retval;
}
@@ -4893,6 +4890,9 @@
unit_load = 100;
status = 0;
+
+ mutex_lock(hcd->address0_mutex);
+
for (i = 0; i < SET_CONFIG_TRIES; i++) {
/* reallocate for each attempt, since references
@@ -4929,6 +4929,8 @@
if (status < 0)
goto loop;
+ mutex_unlock(hcd->address0_mutex);
+
if (udev->quirks & USB_QUIRK_DELAY_INIT)
msleep(2000);
@@ -5017,6 +5019,7 @@
loop_disable:
hub_port_disable(hub, port1, 1);
+ mutex_lock(hcd->address0_mutex);
loop:
usb_ep0_reinit(udev);
release_devnum(udev);
@@ -5043,6 +5046,8 @@
}
done:
+ mutex_unlock(hcd->address0_mutex);
+
hub_port_disable(hub, port1, 1);
if (hcd->driver->relinquish_port && !hub->hdev->parent) {
if (status != -ENOTCONN && status != -ENODEV)
@@ -5572,6 +5577,8 @@
bos = udev->bos;
udev->bos = NULL;
+ mutex_lock(hcd->address0_mutex);
+
for (i = 0; i < SET_CONFIG_TRIES; ++i) {
/* ep0 maxpacket size may change; let the HCD know about it.
@@ -5581,6 +5588,7 @@
if (ret >= 0 || ret == -ENOTCONN || ret == -ENODEV)
break;
}
+ mutex_unlock(hcd->address0_mutex);
if (ret < 0)
goto re_enumerate;