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@xxxxxxxxxxxxxxx> know about it. >From 5ed8d41023751bdd3546f2fe4118304357efe8d2 Mon Sep 17 00:00:00 2001 From: Johan Hovold <johan@xxxxxxxxxx> Date: Thu, 12 Jan 2017 14:56:21 +0100 Subject: USB: serial: spcp8x5: fix modem-status handling From: Johan Hovold <johan@xxxxxxxxxx> 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@xxxxxxxxxxxxxxxxxxx> Signed-off-by: Johan Hovold <johan@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- 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@xxxxxxxxxx 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