Patch "usb: xhci: Handle error condition in xhci_stop_device()" has been added to the 4.9-stable tree

[<gregkh@xxxxxxxxxxxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    usb: xhci: Handle error condition in xhci_stop_device()

to the 4.9-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     usb-xhci-handle-error-condition-in-xhci_stop_device.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.


>From b3207c65dfafae27e7c492cb9188c0dc0eeaf3fd Mon Sep 17 00:00:00 2001
From: Mayank Rana <mrana@xxxxxxxxxxxxxx>
Date: Fri, 6 Oct 2017 17:45:30 +0300
Subject: usb: xhci: Handle error condition in xhci_stop_device()

From: Mayank Rana <mrana@xxxxxxxxxxxxxx>

commit b3207c65dfafae27e7c492cb9188c0dc0eeaf3fd upstream.

xhci_stop_device() calls xhci_queue_stop_endpoint() multiple times
without checking the return value. xhci_queue_stop_endpoint() can
return error if the HC is already halted or unable to queue commands.
This can cause a deadlock condition as xhci_stop_device() would
end up waiting indefinitely for a completion for the command that
didn't get queued. Fix this by checking the return value and bailing
out of xhci_stop_device() in case of error. This patch happens to fix
potential memory leaks of the allocated command structures as well.

Fixes: c311e391a7ef ("xhci: rework command timeout and cancellation,")
Signed-off-by: Mayank Rana <mrana@xxxxxxxxxxxxxx>
Signed-off-by: Jack Pham <jackp@xxxxxxxxxxxxxx>
Signed-off-by: Mathias Nyman <mathias.nyman@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>


---
 drivers/usb/host/xhci-hub.c |   22 +++++++++++++++++-----
 1 file changed, 17 insertions(+), 5 deletions(-)

--- a/drivers/usb/host/xhci-hub.c
+++ b/drivers/usb/host/xhci-hub.c
@@ -412,15 +412,25 @@ static int xhci_stop_device(struct xhci_
 						     GFP_NOWAIT);
 			if (!command) {
 				spin_unlock_irqrestore(&xhci->lock, flags);
-				xhci_free_command(xhci, cmd);
-				return -ENOMEM;
+				ret = -ENOMEM;
+				goto cmd_cleanup;
+			}
 
+			ret = xhci_queue_stop_endpoint(xhci, command, slot_id,
+						       i, suspend);
+			if (ret) {
+				spin_unlock_irqrestore(&xhci->lock, flags);
+				xhci_free_command(xhci, command);
+				goto cmd_cleanup;
 			}
-			xhci_queue_stop_endpoint(xhci, command, slot_id, i,
-						 suspend);
 		}
 	}
-	xhci_queue_stop_endpoint(xhci, cmd, slot_id, 0, suspend);
+	ret = xhci_queue_stop_endpoint(xhci, cmd, slot_id, 0, suspend);
+	if (ret) {
+		spin_unlock_irqrestore(&xhci->lock, flags);
+		goto cmd_cleanup;
+	}
+
 	xhci_ring_cmd_db(xhci);
 	spin_unlock_irqrestore(&xhci->lock, flags);
 
@@ -431,6 +441,8 @@ static int xhci_stop_device(struct xhci_
 		xhci_warn(xhci, "Timeout while waiting for stop endpoint command\n");
 		ret = -ETIME;
 	}
+
+cmd_cleanup:
 	xhci_free_command(xhci, cmd);
 	return ret;
 }


Patches currently in stable-queue which might be from mrana@xxxxxxxxxxxxxx are

queue-4.9/usb-xhci-handle-error-condition-in-xhci_stop_device.patch