[PATCH] mtd: nandsim: remove debugfs entries in error path

[Uwe Kleine-König]

Hello Brian,

On Thu, Aug 24, 2017 at 09:22:03PM -0700, Brian Norris wrote:
> On Wed, Aug 23, 2017 at 09:03:04AM +0200, Uwe Kleine-König wrote:
> > The debugfs entries must be removed before an error is returned in the
> > probe function. Otherwise another try to load the module fails and when
> > the debugfs files are accessed without the module loaded, the kernel
> > still tries to call a function in that module.
> > 
> > Fixes: 5346c27c5fed ("mtd: nandsim: Introduce debugfs infrastructure")
> > Signed-off-by: Uwe Kleine-König <u.kleine-koenig at pengutronix.de>
> > ---
> >  drivers/mtd/nand/nandsim.c | 1 +
> >  1 file changed, 1 insertion(+)
> > 
> > diff --git a/drivers/mtd/nand/nandsim.c b/drivers/mtd/nand/nandsim.c
> > index 03a0d057bf2f..e4211c3cc49b 100644
> > --- a/drivers/mtd/nand/nandsim.c
> > +++ b/drivers/mtd/nand/nandsim.c
> > @@ -2373,6 +2373,7 @@ static int __init ns_init_module(void)
> >          return 0;
> >  
> >  err_exit:
> > +	nandsim_debugfs_remove(nand);
> 
> The 'err_exit' label is used by error paths that occur before the
> debugfs entries are registered. But I guess that's OK, since
> debugfs_remove_recursive() handles NULL arguments fine?

Yes. 
 
> We also have the same mismatch with init_nandsim()/free_nandsim(), which
> is also similarly safe because of the nature of kfree(), vfree(), and
> the fact that most of those are guarded with NULL checks anyway... So
> it's just confusing and potentially dangerous for future developers --
> but not wrong.

Ack, I took me some time to find a right place for
nandsim_debugfs_remove because I had problems to match the cleanup
functions in the error path to the setup functions. I then stopped
checking the already existing code for correctness and just put
nandsim_debugfs_remove to a place that works.

> I'll look to queue this up and send to Linus within a day.

\o/

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |