xhci: don't create endpoint debugfs entry before ring buffer is set.

[ Upstream commit 167657a1bb5fcde53ac304ce6c564bd90a2f9185 ]

Make sure xHC completes the configure endpoint command and xhci driver
sets the ring pointers correctly before we create the user readable
debugfs file.

In theory there was a small gap where a user could have read the
debugfs file and cause a NULL pointer dereference error as ring
pointer was not yet set, in practise we want this change to simplify
the upcoming streams debugfs support.

Fixes: 02b6fdc2a153 ("usb: xhci: Add debugfs interface for xHCI driver")
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20200918131752.16488-10-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index 113ab5d3cbfe52fdea931929bbf351027796389f..f665da34a8f7390a0cbf70d90e7db64df7ac6017 100644 (file)
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -1915,8 +1915,6 @@ static int xhci_add_endpoint(struct usb_hcd *hcd, struct usb_device *udev,
        ep_ctx = xhci_get_ep_ctx(xhci, virt_dev->in_ctx, ep_index);
        trace_xhci_add_endpoint(ep_ctx);
 
-       xhci_debugfs_create_endpoint(xhci, virt_dev, ep_index);
-
        xhci_dbg(xhci, "add ep 0x%x, slot id %d, new drop flags = %#x, new add flags = %#x\n",
                        (unsigned int) ep->desc.bEndpointAddress,
                        udev->slot_id,
@@ -2949,6 +2947,7 @@ static int xhci_check_bandwidth(struct usb_hcd *hcd, struct usb_device *udev)
                xhci_check_bw_drop_ep_streams(xhci, virt_dev, i);
                virt_dev->eps[i].ring = virt_dev->eps[i].new_ring;
                virt_dev->eps[i].new_ring = NULL;
+               xhci_debugfs_create_endpoint(xhci, virt_dev, i);
        }
 command_cleanup:
        kfree(command->completion);