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USB: serial: cyberjack: fix write-URB completion race 

The write-URB busy flag was being cleared before the completion handler
was done with the URB, something which could lead to corrupt transfers
due to a racing write request if the URB is resubmitted.

Fixes: 507ca9bc04 ("[PATCH] USB: add ability for usb-serial drivers to determine if their write urb is currently being used.")
Cc: stable <stable@vger.kernel.org>     # 2.6.13
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
This commit is contained in:
Johan Hovold 2020-10-26 09:25:48 +01:00
parent a46b973bce
commit 985616f045
1 changed files with 6 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
drivers/usb/serial/cyberjack.c
View File

@ -357,11 +357,12 @@ static void cyberjack_write_bulk_callback(struct urb *urb)
struct device *dev = &port->dev;
int status = urb->status;
unsigned long flags;
bool resubmitted = false;
set_bit(0, &port->write_urbs_free);
if (status) {
dev_dbg(dev, "%s - nonzero write bulk status received: %d\n",
__func__, status);
set_bit(0, &port->write_urbs_free);
return;
}
@ -394,6 +395,8 @@ static void cyberjack_write_bulk_callback(struct urb *urb)
goto exit;
}
resubmitted = true;
dev_dbg(dev, "%s - priv->wrsent=%d\n", __func__, priv->wrsent);
dev_dbg(dev, "%s - priv->wrfilled=%d\n", __func__, priv->wrfilled);
@ -410,6 +413,8 @@ static void cyberjack_write_bulk_callback(struct urb *urb)
exit:
spin_unlock_irqrestore(&priv->lock, flags);
if (!resubmitted)
set_bit(0, &port->write_urbs_free);
usb_serial_port_softint(port);
}