On Sat, Dec 21, 2024 at 10:25:41AM +0100, Greg KH wrote:
> On Sat, Dec 21, 2024 at 02:41:25PM +0530, Nihar Chaithanya wrote:
> > The if condition in cb7210_init_module() would always fail as
> > the value of err is constantly 0. The function
> > cb_pcmcia_init_module() can be refactored into a single line,
> > and can be replaced entirely with pcmcia_register_driver().
> >
> > Replace redundant cb_pcmcia_init_module() with
> > pcmcia_register_driver() which returns appropriate error code if
> > it fails. Handle the error if it fails and print the debug message.
> >
> > This issue was reported by Coverity Scan.
> > Report:
> > CID 1635894: (#1 of 1): 'Constant' variable guards dead code (DEADCODE)
> > dead_error_line: Execution cannot reach this statement: return -1;.
> >
> > Signed-off-by: Nihar Chaithanya <niharchaithanya@xxxxxxxxx>
> > ---
> > v1 --> v2: Replaced the redundant cb_pcmcia_init_module() with
> > pcmcia_register_driver().
> >
> > drivers/staging/gpib/cb7210/cb7210.c | 13 ++++---------
> > 1 file changed, 4 insertions(+), 9 deletions(-)
> >
> > diff --git a/drivers/staging/gpib/cb7210/cb7210.c b/drivers/staging/gpib/cb7210/cb7210.c
> > index 63df7f3eb3f3..abd6632d8448 100644
> > --- a/drivers/staging/gpib/cb7210/cb7210.c
> > +++ b/drivers/staging/gpib/cb7210/cb7210.c
> > @@ -1351,12 +1351,6 @@ static struct pcmcia_driver cb_gpib_cs_driver = {
> > .resume = cb_gpib_resume,
> > };
> >
> > -int cb_pcmcia_init_module(void)
> > -{
> > - pcmcia_register_driver(&cb_gpib_cs_driver);
> > - return 0;
> > -}
> > -
> > void cb_pcmcia_cleanup_module(void)
> > {
> > DEBUG(0, "cb_gpib_cs: unloading\n");
> > @@ -1526,11 +1520,12 @@ static int __init cb7210_init_module(void)
> > gpib_register_driver(&cb_pcmcia_interface, THIS_MODULE);
> > gpib_register_driver(&cb_pcmcia_accel_interface, THIS_MODULE);
> > gpib_register_driver(&cb_pcmcia_unaccel_interface, THIS_MODULE);
> > - err += cb_pcmcia_init_module();
> > + err = pcmcia_register_driver(&cb_gpib_cs_driver);
> > #endif
> > - if (err)
> > + if (err) {
> > + pr_err("cb7210: registering PCMCIA driver with the bus core failed\n");
> > return -1;
>
> Not your issue, but "-1" is not a valid error number, shouldn't this be
> returning a real error (i.e. the one that was returned?)
>
> And err += is crazy, thanks for removing that, BUT you forgot to unwind
> the previous functions so now if pcmcia_register_driver() fails, you
> have a semi-registered system and then the module will unload (as init
> fails) and bad things will happen :(
>
> So you kind of just made the code worse overall, not better, which
> really isn't a good idea for a "bugfix" that covertity was trying to
> point out.
And (this is taking you down a path that is much larger than you
expected to just fix this one issue, sorry), it looks like
gpib_register_driver() can fail, so it MUST return an error value so you
can properly unwind from it. So that too needs to be fixed up here
(also minor nit, gpib_register_driver() should not be calling pr_info(),
but that's a different issue.)
In all, there are loads of tiny things like this to fix up in the gpib
code, which is great, have fun!
thanks,
greg k-h
