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Commit 96c706ed authored by Oliver Neukum's avatar Oliver Neukum Committed by Greg Kroah-Hartman
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USB: io_edgeport race condition in counters 



io_edgeport is using a global variable without locking.
This is _the_ classical race condition. This patch switches to atomic_t.

Signed-off-by: default avatarOliver Neukum <oneukum@suse.de>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent e198a314

drivers/usb/serial/io_edgeport.c

+7 −6
Original line number Diff line number Diff line
@@ -212,7 +212,7 @@ static int debug; 


static int low_latency = 1;	/* tty low latency flag, on by default */



static int CmdUrbs = 0;		/* Number of outstanding Command Write Urbs */

static atomic_t CmdUrbs;		/* Number of outstanding Command Write Urbs */





/* local function prototypes */
@@ -779,8 +779,8 @@ static void edge_bulk_out_cmd_callback (struct urb *urb) 


	dbg("%s", __FUNCTION__);



	CmdUrbs--;

	dbg("%s - FREE URB %p (outstanding %d)", __FUNCTION__, urb, CmdUrbs);

	atomic_dec(&CmdUrbs);

	dbg("%s - FREE URB %p (outstanding %d)", __FUNCTION__, urb, atomic_read(&CmdUrbs));





	/* clean up the transfer buffer */
@@ -2317,8 +2317,8 @@ static int write_cmd_usb (struct edgeport_port *edge_port, unsigned char *buffer 
	if (!urb)

		return -ENOMEM;



	CmdUrbs++;

	dbg("%s - ALLOCATE URB %p (outstanding %d)", __FUNCTION__, urb, CmdUrbs);

	atomic_inc(&CmdUrbs);

	dbg("%s - ALLOCATE URB %p (outstanding %d)", __FUNCTION__, urb, atomic_read(&CmdUrbs));



	usb_fill_bulk_urb (urb, edge_serial->serial->dev, 

		       usb_sndbulkpipe(edge_serial->serial->dev, edge_serial->bulk_out_endpoint),
@@ -2332,7 +2332,7 @@ static int write_cmd_usb (struct edgeport_port *edge_port, unsigned char *buffer 
		dev_err(&edge_port->port->dev, "%s - usb_submit_urb(write command) failed, status = %d\n", __FUNCTION__, status);

		usb_kill_urb(urb);

		usb_free_urb(urb);

		CmdUrbs--;

		atomic_dec(&CmdUrbs);

		return status;

	}
@@ -3083,6 +3083,7 @@ static int __init edgeport_init(void) 
	retval = usb_register(&io_driver);

	if (retval) 

		goto failed_usb_register;

	atomic_set(&CmdUrbs, 0);

	info(DRIVER_DESC " " DRIVER_VERSION);

	return 0;