From: Mathias Nyman <mathias.nyman@xxxxxxxxxxxxxxx>
commit cfbb8a84c2d2ef49bccacb511002bca4f6053555 upstream.
udev stored in ep->hcpriv might be NULL if tt buffer is cleared
due to a halted control endpoint during device enumeration
xhci_clear_tt_buffer_complete is called by hub_tt_work() once it's
scheduled, and by then usb core might have freed and allocated a
new udev for the next enumeration attempt.
Fixes: ef513be0a905 ("usb: xhci: Add Clear_TT_Buffer")
Cc: <stable@xxxxxxxxxxxxxxx> # v5.3
Reported-by: Johan Hovold <johan@xxxxxxxxxx>
Signed-off-by: Mathias Nyman <mathias.nyman@xxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/1570190373-30684-9-git-send-email-mathias.nyman@xxxxxxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/usb/host/xhci.c | 8 ++++++++
1 file changed, 8 insertions(+)
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -5237,8 +5237,16 @@ static void xhci_clear_tt_buffer_complet
unsigned int ep_index;
unsigned long flags;
+ /*
+ * udev might be NULL if tt buffer is cleared during a failed device
+ * enumeration due to a halted control endpoint. Usb core might
+ * have allocated a new udev for the next enumeration attempt.
+ */
+
xhci = hcd_to_xhci(hcd);
udev = (struct usb_device *)ep->hcpriv;
+ if (!udev)
+ return;
slot_id = udev->slot_id;
ep_index = xhci_get_endpoint_index(&ep->desc);
