Patch "USB: serial: spcp8x5: fix modem-status handling" has been added to the 4.4-stable tree

[<gregkh@linuxfoundation.org>]

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

    USB: serial: spcp8x5: fix modem-status handling

to the 4.4-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-serial-spcp8x5-fix-modem-status-handling.patch
and it can be found in the queue-4.4 subdirectory.

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


>From 5ed8d41023751bdd3546f2fe4118304357efe8d2 Mon Sep 17 00:00:00 2001
From: Johan Hovold <johan@kernel.org>
Date: Thu, 12 Jan 2017 14:56:21 +0100
Subject: USB: serial: spcp8x5: fix modem-status handling

From: Johan Hovold <johan@kernel.org>

commit 5ed8d41023751bdd3546f2fe4118304357efe8d2 upstream.

Make sure to detect short control transfers and return zero on success
when retrieving the modem status.

This fixes the TIOCMGET implementation which since e1ed212d8593 ("USB:
spcp8x5: add proper modem-status support") has returned TIOCM_LE on
successful retrieval, and avoids leaking bits from the stack on short
transfers.

This also fixes the carrier-detect implementation which since the above
mentioned commit unconditionally has returned true.

Fixes: e1ed212d8593 ("USB: spcp8x5: add proper modem-status support")
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/usb/serial/spcp8x5.c |    8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

--- a/drivers/usb/serial/spcp8x5.c
+++ b/drivers/usb/serial/spcp8x5.c
@@ -232,11 +232,17 @@ static int spcp8x5_get_msr(struct usb_se
 	ret = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
 			      GET_UART_STATUS, GET_UART_STATUS_TYPE,
 			      0, GET_UART_STATUS_MSR, buf, 1, 100);
-	if (ret < 0)
+	if (ret < 1) {
 		dev_err(&port->dev, "failed to get modem status: %d\n", ret);
+		if (ret >= 0)
+			ret = -EIO;
+		goto out;
+	}
 
 	dev_dbg(&port->dev, "0xc0:0x22:0:6  %d - 0x02%x\n", ret, *buf);
 	*status = *buf;
+	ret = 0;
+out:
 	kfree(buf);
 
 	return ret;


Patches currently in stable-queue which might be from johan@kernel.org are

queue-4.4/usb-serial-ftdi_sio-fix-modem-status-error-handling.patch
queue-4.4/usb-serial-cp210x-add-new-ids-for-ge-bx50v3-boards.patch
queue-4.4/usb-serial-ark3116-fix-register-accessor-error-handling.patch
queue-4.4/usb-serial-digi_acceleport-fix-oob-data-sanity-check.patch
queue-4.4/usb-serial-ftdi_sio-fix-line-status-over-reporting.patch
queue-4.4/usb-serial-ftdi_sio-fix-extreme-low-latency-setting.patch
queue-4.4/usb-serial-spcp8x5-fix-modem-status-handling.patch
queue-4.4/usb-serial-opticon-fix-cts-retrieval-at-open.patch
queue-4.4/usb-serial-mos7840-fix-another-null-deref-at-open.patch