[3.16.y-ckt stable] Patch "usb: xhci: lock mutex on xhci_stop" has been added to staging queue

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    usb: xhci: lock mutex on xhci_stop

to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.16.y-queue

This patch is scheduled to be released in version 3.19.8-ckt9.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.16.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From d27dd79d68e24ced4f52d3f9995612481a7acaf0 Mon Sep 17 00:00:00 2001
From: Roger Quadros <rogerq at ti.com>
Date: Mon, 21 Sep 2015 17:46:12 +0300
Subject: usb: xhci: lock mutex on xhci_stop

commit 85ac90f8953a58f6a057b727bc9db97721e3fb8e upstream.

Else it races with xhci_setup_device

Signed-off-by: Roger Quadros <rogerq at ti.com>
Signed-off-by: Mathias Nyman <mathias.nyman at linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/usb/host/xhci.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index f2194a0..0c4ea93 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -686,8 +686,11 @@ void xhci_stop(struct usb_hcd *hcd)
 	u32 temp;
 	struct xhci_hcd *xhci = hcd_to_xhci(hcd);

+	mutex_lock(&xhci->mutex);
+
 	if (!usb_hcd_is_primary_hcd(hcd)) {
 		xhci_only_stop_hcd(xhci->shared_hcd);
+		mutex_unlock(&xhci->mutex);
 		return;
 	}

@@ -726,6 +729,7 @@ void xhci_stop(struct usb_hcd *hcd)
 	xhci_dbg_trace(xhci, trace_xhci_dbg_init,
 			"xhci_stop completed - status = %x",
 			readl(&xhci->op_regs->status));
+	mutex_unlock(&xhci->mutex);
 }

 /*
--
1.9.1