From cfbb8a84c2d2ef49bccacb511002bca4f6053555 Mon Sep 17 00:00:00 2001 From: Mathias Nyman Date: Fri, 4 Oct 2019 14:59:33 +0300 Subject: [PATCH] xhci: Fix NULL pointer dereference in xhci_clear_tt_buffer_complete() 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: # v5.3 Reported-by: Johan Hovold Signed-off-by: Mathias Nyman Link: https://lore.kernel.org/r/1570190373-30684-9-git-send-email-mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman --- drivers/usb/host/xhci.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c index 00f3804..517ec32 100644 --- a/drivers/usb/host/xhci.c +++ b/drivers/usb/host/xhci.c @@ -5238,8 +5238,16 @@ static void xhci_clear_tt_buffer_complete(struct usb_hcd *hcd, 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); -- 2.7.4