From a400efe455f7b61ac9a801ac8d0d01f8c8d82dd5 Mon Sep 17 00:00:00 2001
From: Mathias Nyman <mathias.nyman@linux.intel.com>
Date: Fri, 16 Mar 2018 16:33:01 +0200
Subject: [PATCH] xhci: zero usb device slot_id member when disabling and
 freeing a xhci slot
Git-commit: a400efe455f7b61ac9a801ac8d0d01f8c8d82dd5
Patch-mainline: v4.17-rc1
References: bsc#1090888

set udev->slot_id to zero when disabling and freeing the xhci slot.
Prevents usb core from calling xhci with a stale slot id.

xHC controller may be reset during resume to recover from some error.
All slots are unusable as they are disabled and freed.
xhci driver starts slot enumeration again from 1 in the order they are
enabled. In the worst case a stale udev->slot_id for one device matches
a newly enabled slot_id for a different device, causing us to
perform a action on the wrong device.

Signed-off-by: Mathias Nyman <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-mem.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c
index 332420d10be9..e5ace8995b3b 100644
--- a/drivers/usb/host/xhci-mem.c
+++ b/drivers/usb/host/xhci-mem.c
@@ -913,6 +913,8 @@ void xhci_free_virt_device(struct xhci_hcd *xhci, int slot_id)
 	if (dev->out_ctx)
 		xhci_free_container_ctx(xhci, dev->out_ctx);
 
+	if (dev->udev && dev->udev->slot_id)
+		dev->udev->slot_id = 0;
 	kfree(xhci->devs[slot_id]);
 	xhci->devs[slot_id] = NULL;
 }
-- 
2.16.4