From 7e0b1b60cb0d7d3ae4c22a891e11ceccca17afee Mon Sep 17 00:00:00 2001 From: Ian Abbott Date: Fri, 22 May 2015 16:21:35 +0100 Subject: [PATCH] staging: comedi: 8255: fix I/O region leak on failure The Comedi "8255" driver does not clean up properly on failure. It can leave requested I/O port regions unreleased. Specifically, the Comedi "attach" handler (`dev_8255_attach()`) requests a specified I/O port region before calling `subdev_8255_init()` to set up the subdevice. If that fails, the "attach" handler returns an error and the Comedi core will call the "detach" handler (`dev_8255_detach()`) to clean up. The "detach" handler is responsible for releasing the I/O port regions successfully requested by the "attach" handler. Unfortunately, it is unable to obtain the base address of the region if the call to `subdev_8255_init()` failed. Fix the I/O region leak by releasing the region in the "attach" handler directly if the call to `subdev_8255_init()` fails. Signed-off-by: Ian Abbott Reviewed-by: H Hartley Sweeten Signed-off-by: Greg Kroah-Hartman --- drivers/staging/comedi/drivers/8255.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/drivers/staging/comedi/drivers/8255.c b/drivers/staging/comedi/drivers/8255.c index ba89321df65d..0fdf8342c995 100644 --- a/drivers/staging/comedi/drivers/8255.c +++ b/drivers/staging/comedi/drivers/8255.c @@ -306,8 +306,15 @@ static int dev_8255_attach(struct comedi_device *dev, s->type = COMEDI_SUBD_UNUSED; } else { ret = subdev_8255_init(dev, s, NULL, iobase); - if (ret) + if (ret) { + /* + * Release the I/O port region here, as the + * "detach" handler cannot find it. + */ + release_region(iobase, I8255_SIZE); + s->type = COMEDI_SUBD_UNUSED; return ret; + } } } -- 2.11.0