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: Oliver Neukum <oneukum@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/usb/serial/io_edgeport.c b/drivers/usb/serial/io_edgeport.c
index 6a26a2e..187fd42 100644
--- a/drivers/usb/serial/io_edgeport.c
+++ b/drivers/usb/serial/io_edgeport.c
@@ -212,7 +212,7 @@
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 @@
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 @@
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 @@
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 @@
retval = usb_register(&io_driver);
if (retval)
goto failed_usb_register;
+ atomic_set(&CmdUrbs, 0);
info(DRIVER_DESC " " DRIVER_VERSION);
return 0;
