From 101ab946b79ad83b36d5cfd47de587492a80acf0 Mon Sep 17 00:00:00 2001 From: Ian Abbott Date: Wed, 28 Jan 2026 15:00:10 +0000 Subject: comedi: ni_atmio16d: Fix invalid clean-up after failed attach If the driver's COMEDI "attach" handler function (`atmio16d_attach()`) returns an error, the COMEDI core will call the driver's "detach" handler function (`atmio16d_detach()`) to clean up. This calls `reset_atmio16d()` unconditionally, but depending on where the error occurred in the attach handler, the device may not have been sufficiently initialized to call `reset_atmio16d()`. It uses `dev->iobase` as the I/O port base address and `dev->private` as the pointer to the COMEDI device's private data structure. `dev->iobase` may still be set to its initial value of 0, which would result in undesired writes to low I/O port addresses. `dev->private` may still be `NULL`, which would result in null pointer dereferences. Fix `atmio16d_detach()` by checking that `dev->private` is valid (non-null) before calling `reset_atmio16d()`. This implies that `dev->iobase` was set correctly since that is set up before `dev->private`. Fixes: 2323b276308a ("Staging: comedi: add ni_at_atmio16d driver") Cc: stable Signed-off-by: Ian Abbott Link: https://patch.msgid.link/20260128150011.5006-1-abbotti@mev.co.uk Signed-off-by: Greg Kroah-Hartman --- drivers/comedi/drivers/ni_atmio16d.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/comedi/drivers/ni_atmio16d.c b/drivers/comedi/drivers/ni_atmio16d.c index e5e7cc423c87..b057b3b3582e 100644 --- a/drivers/comedi/drivers/ni_atmio16d.c +++ b/drivers/comedi/drivers/ni_atmio16d.c @@ -698,7 +698,8 @@ static int atmio16d_attach(struct comedi_device *dev, static void atmio16d_detach(struct comedi_device *dev) { - reset_atmio16d(dev); + if (dev->private) + reset_atmio16d(dev); comedi_legacy_detach(dev); } -- cgit v1.2.3