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 <abbotti@mev.co.uk>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/staging/comedi/drivers/8255.c b/drivers/staging/comedi/drivers/8255.c
index ba89321..0fdf834 100644
--- a/drivers/staging/comedi/drivers/8255.c
+++ b/drivers/staging/comedi/drivers/8255.c
@@ -306,8 +306,15 @@
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;
+ }
}
}