Patch "USB: serial: io_edgeport: fix possible sleep-in-atomic" has been added to the 4.9-stable tree

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

USB: serial: io_edgeport: fix possible sleep-in-atomic

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-serial-io_edgeport-fix-possible-sleep-in-atomic.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 <[email protected]> know about it.

From: Jia-Ju Bai <[email protected]>
Date: Wed, 13 Dec 2017 20:34:36 +0800
Subject: USB: serial: io_edgeport: fix possible sleep-in-atomic

From: Jia-Ju Bai <[email protected]>

commit c7b8f77872c73f69a16528a9eb87afefcccdc18b upstream.

According to drivers/usb/serial/io_edgeport.c, the driver may sleep under a spinlock.
The function call path is:
edge_bulk_in_callback (acquire the spinlock)
process_rcvd_data

     process_rcvd_status
       change_port_settings
         send_iosp_ext_cmd
           write_cmd_usb
             usb_kill_urb --> may sleep

To fix it, the redundant usb_kill_urb() is removed from the error path after usb_submit_urb() fails.

This possible bug is found by my static analysis tool (DSAC) and checked by my code review.

---
 drivers/usb/serial/io_edgeport.c |    1 -
 1 file changed, 1 deletion(-)

@@ -2215,7 +2215,6 @@ static int write_cmd_usb(struct edgeport
 		/* something went wrong */
 		dev_err(dev, "%s - usb_submit_urb(write command) failed, status = %d\n",
 			__func__, status);
-		usb_kill_urb(urb);
 		usb_free_urb(urb);
 		atomic_dec(&CmdUrbs);
 		return status;

Patches currently in stable-queue which might be from [email protected] are

queue-4.9/usb-serial-io_edgeport-fix-possible-sleep-in-atomic.patch