`pc236_detach()` is called by the comedi core to clean up if either
`pc236_attach()` or `pc236_attach_pci()` returns an error. It sets
`thisboard` to the return value of `comedi_board(dev)` and assumes it is
non-null. This is a valid assumption if `pc236_attach()` fails, but not
if `pc236_attach_pci()` fails, leading to a possible NULL pointer
dereference.
Check `thisboard` at the top of `pc236_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: <stable@xxxxxxxxxxxxxxx> # 3.6.x
Signed-off-by: Ian Abbott <abbotti@xxxxxxxxx>
---
drivers/staging/comedi/drivers/amplc_pc236.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/staging/comedi/drivers/amplc_pc236.c b/drivers/staging/comedi/drivers/amplc_pc236.c
index 36768b2..4e4f3c1 100644
--- a/drivers/staging/comedi/drivers/amplc_pc236.c
+++ b/drivers/staging/comedi/drivers/amplc_pc236.c
@@ -574,6 +574,8 @@ static void pc236_detach(struct comedi_device *dev)
{
const struct pc236_board *thisboard = comedi_board(dev);
+ if (!thisboard)
+ return;
if (dev->iobase)
pc236_intr_disable(dev);
if (dev->irq)
--
1.7.12
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