[PATCH]io_edgeport race condition in counters
Oliver Neukum <[email protected]>
| Newsgroups | gmane.linux.usb.devel |
|---|---|
| Organization | Novell |
| Message-ID | <[email protected]> |
Hi, io_edgeport is using a global variable without locking. This is _the_ classical race condition. This patch switches to atomic_t. Regards Oliver Signed-off-by: Oliver Neukum <[email protected]> -- --- a/drivers/usb/serial/io_edgeport.c 2007-03-12 19:31:50.000000000 +0100 +++ b/drivers/usb/serial/io_edgeport.c 2007-03-15 15:20:27.000000000 +0100 @@ -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; ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys-and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ [email protected] To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel