From 3955dfa8216f712bc204a5ad2f4e51efff252fde Mon Sep 17 00:00:00 2001 From: Ian Abbott Date: Fri, 23 Aug 2013 12:37:17 +0100 Subject: [PATCH] staging: comedi: bug-fix NULL pointer dereference on failed attach Commit dcd7b8bd63cb81c5b973bf86510ca3c80bbbd162 ("staging: comedi: put module _after_ detach" by myself) reversed a couple of calls in `comedi_device_attach()` when recovering from an error returned by the low-level driver's 'attach' handler. Unfortunately, that introduced a NULL pointer dereference bug as `dev->driver` is NULL after the call to `comedi_device_detach()`. We still have a pointer to the low-level comedi driver structure in the `driv` variable, so use that instead. Signed-off-by: Ian Abbott Cc: # 3.10+ Signed-off-by: Greg Kroah-Hartman --- drivers/staging/comedi/drivers.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/staging/comedi/drivers.c b/drivers/staging/comedi/drivers.c index e25eba5..b3b5125 100644 --- a/drivers/staging/comedi/drivers.c +++ b/drivers/staging/comedi/drivers.c @@ -482,7 +482,7 @@ int comedi_device_attach(struct comedi_device *dev, struct comedi_devconfig *it) ret = comedi_device_postconfig(dev); if (ret < 0) { comedi_device_detach(dev); - module_put(dev->driver->module); + module_put(driv->module); } /* On success, the driver module count has been incremented. */ return ret; -- 2.7.4