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usb: hub: Fix usb enumeration issue due to address0 race

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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: 638139eb95 ("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>
This commit is contained in:
Mathias Nyman 2021-11-16 00:16:30 +02:00 committed by Greg Kroah-Hartman
parent 362468830d
commit 6ae6dc22d2
1 changed files with 11 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

14
drivers/usb/core/hub.c
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@ -4700,8 +4700,6 @@ hub_port_init(struct usb_hub *hub, struct usb_device *udev, int port1,
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);
@ -5016,7 +5014,6 @@ fail:
hub_port_disable(hub, port1, 0);
update_devnum(udev, devnum); /* for disconnect processing */
}
mutex_unlock(hcd->address0_mutex);
return retval;
}
@ -5246,6 +5243,9 @@ static void hub_port_connect(struct usb_hub *hub, int port1, u16 portstatus,
unit_load = 100;
status = 0;
mutex_lock(hcd->address0_mutex);
for (i = 0; i < PORT_INIT_TRIES; i++) {
/* reallocate for each attempt, since references
@ -5282,6 +5282,8 @@ static void hub_port_connect(struct usb_hub *hub, int port1, u16 portstatus,
if (status < 0)
goto loop;
mutex_unlock(hcd->address0_mutex);
if (udev->quirks & USB_QUIRK_DELAY_INIT)
msleep(2000);
@ -5370,6 +5372,7 @@ static void hub_port_connect(struct usb_hub *hub, int port1, u16 portstatus,
loop_disable:
hub_port_disable(hub, port1, 1);
mutex_lock(hcd->address0_mutex);
loop:
usb_ep0_reinit(udev);
release_devnum(udev);
@ -5396,6 +5399,8 @@ loop:
}
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)
@ -5915,6 +5920,8 @@ static int usb_reset_and_verify_device(struct usb_device *udev)
bos = udev->bos;
udev->bos = NULL;
mutex_lock(hcd->address0_mutex);
for (i = 0; i < PORT_INIT_TRIES; ++i) {
/* ep0 maxpacket size may change; let the HCD know about it.
@ -5924,6 +5931,7 @@ static int usb_reset_and_verify_device(struct usb_device *udev)
if (ret >= 0 || ret == -ENOTCONN || ret == -ENODEV)
break;
}
mutex_unlock(hcd->address0_mutex);
if (ret < 0)
goto re_enumerate;