From 167657a1bb5fcde53ac304ce6c564bd90a2f9185 Mon Sep 17 00:00:00 2001
From: Mathias Nyman <mathias.nyman@linux.intel.com>
Date: Fri, 18 Sep 2020 16:17:51 +0300
Subject: [PATCH] xhci: don't create endpoint debugfs entry before ring buffer
 is set.
Git-commit: 167657a1bb5fcde53ac304ce6c564bd90a2f9185
References: git-fixes
Patch-mainline: v5.10-rc1

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: Oliver Neukum <oneukum@suse.com>
---
 drivers/usb/host/xhci.c |    3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -1899,8 +1899,6 @@ static int xhci_add_endpoint(struct usb_
 	/* Store the usb_device pointer for later use */
 	ep->hcpriv = udev;
 
-	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,
@@ -2927,6 +2925,7 @@ static int xhci_check_bandwidth(struct u
 		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);