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xhci: Fix null pointer dereference during S4 resume when resetting ep0

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During device enumeration usb core resets endpoint 0 if the max packet
size value differs from the one read from the device descriptor.

usb core will additionally reset endpoint 0 during S4 resume, before
re-enumerating the device, if the device has a reset-resume flag set.

In this case the xhci device representation vdev may be lost due to
xHC restore error and re-initialization during S4 resume.

Make sure slot_id and vdev are valid before trying to re-configure max
packet size during endpoint 0 reset.
max packet size will be re-configured later during re-enumeration.

This fixes commit e34900f46c ("xhci: Reconfigure endpoint 0 max packet
size only during endpoint reset") which is currently in usb-next,
on its way to 6.8

Fixes: e34900f46c ("xhci: Reconfigure endpoint 0 max packet size only during endpoint reset")
Tested-by: Wendy Wang <wendy.wang@intel.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20231215125707.1732989-2-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Mathias Nyman 2023-12-15 14:57:07 +02:00 committed by Greg Kroah-Hartman
parent c084af69a8
commit 80602b6b5a
1 changed files with 13 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

20
drivers/usb/host/xhci.c
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@ -3077,6 +3077,9 @@ done:
* of an endpoint that isn't in the halted state this function will issue a
* configure endpoint command with the Drop and Add bits set for the target
* endpoint. Refer to the additional note in xhci spcification section 4.6.8.
*
* vdev may be lost due to xHC restore error and re-initialization during S3/S4
* resume. A new vdev will be allocated later by xhci_discover_or_reset_device()
*/
static void xhci_endpoint_reset(struct usb_hcd *hcd,
@ -3102,9 +3105,17 @@ static void xhci_endpoint_reset(struct usb_hcd *hcd,
* mismatch. Reconfigure the xhci ep0 endpoint context here in that case
*/
if (usb_endpoint_xfer_control(&host_ep->desc) && ep_index == 0) {
udev = container_of(host_ep, struct usb_device, ep0);
if (udev->speed == USB_SPEED_FULL)
xhci_check_ep0_maxpacket(xhci, xhci->devs[udev->slot_id]);
if (udev->speed != USB_SPEED_FULL || !udev->slot_id)
return;
vdev = xhci->devs[udev->slot_id];
if (!vdev || vdev->udev != udev)
return;
xhci_check_ep0_maxpacket(xhci, vdev);
/* Nothing else should be done here for ep0 during ep reset */
return;
}
@ -3114,11 +3125,6 @@ static void xhci_endpoint_reset(struct usb_hcd *hcd,
udev = (struct usb_device *) host_ep->hcpriv;
vdev = xhci->devs[udev->slot_id];
/*
* vdev may be lost due to xHC restore error and re-initialization
* during S3/S4 resume. A new vdev will be allocated later by
* xhci_discover_or_reset_device()
*/
if (!udev->slot_id || !vdev)
return;