`labpc_common_detach()` is called by the comedi core to clean up if either `labpc_attach()` (including the one in the "ni_labpc_cs" module) or `labpc_attach_pci()` returns an error. It assumes the `thisboard` macro (expanding to `((struct labpc_board_struct *)dev->board_ptr)`) is non-null. This is a valid assumption if `labpc_attach()` fails, but not if `labpc_attach_pci()` fails, leading to a possible NULL pointer dereference.
Check `thisboard` at the top of `labpc_common_detach()` and return early if it is `NULL`. This is okay because the only other thing that could have been allocated is `dev->private` and that is freed by the comedi core, not by this function. Cc: <[email protected]> # 3.6.x Signed-off-by: Ian Abbott <[email protected]> --- drivers/staging/comedi/drivers/ni_labpc.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/staging/comedi/drivers/ni_labpc.c b/drivers/staging/comedi/drivers/ni_labpc.c index 28b91a6..b5a19a0 100644 --- a/drivers/staging/comedi/drivers/ni_labpc.c +++ b/drivers/staging/comedi/drivers/ni_labpc.c @@ -772,6 +772,8 @@ void labpc_common_detach(struct comedi_device *dev) { struct comedi_subdevice *s; + if (!thisboard) + return; if (dev->subdevices) { s = &dev->subdevices[2]; subdev_8255_cleanup(dev, s); -- 1.7.12 _______________________________________________ devel mailing list [email protected] http://driverdev.linuxdriverproject.org/mailman/listinfo/devel
