Re: [PATCH 5.10] staging: gasket: interrupt: Clean interrupt_data after free

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Tue, May 16, 2023 at 01:44:06PM +0300, Ekaterina Esina wrote:
> 
> 
> On 15.05.2023 16:02, Greg Kroah-Hartman wrote:
> > On Mon, May 15, 2023 at 03:29:50PM +0300, Esina Ekaterina wrote:
> > > Add interrupt_data = NULL after kfree(interrupt_data) in
> > > gasket_interrupt_init. It is needed to avoid double free
> > > in gasket_interrupt_cleanup, there is a check for NULL
> > > before kfree(interrupt_data).
> > > 
> > > Found by Astra Linux on behalf of Linux Verification Center
> > > (linuxtesting.org) with SVACE.
> > > 
> > > Fixes: 9a69f5087ccc ("drivers/staging: Gasket driver framework + Apex driver")
> > > Signed-off-by: Esina Ekaterina <eesina@astralinux.ru>
> > > ---
> > >   drivers/staging/gasket/gasket_interrupt.c | 2 ++
> > >   1 file changed, 2 insertions(+)
> > > 
> > > diff --git a/drivers/staging/gasket/gasket_interrupt.c b/drivers/staging/gasket/gasket_interrupt.c
> > > index 864342acfd86..48b664b9134a 100644
> > > --- a/drivers/staging/gasket/gasket_interrupt.c
> > > +++ b/drivers/staging/gasket/gasket_interrupt.c
> > > @@ -337,6 +337,7 @@ int gasket_interrupt_init(struct gasket_dev *gasket_dev)
> > >   			sizeof(*interrupt_data->eventfd_ctxs), GFP_KERNEL);
> > >   	if (!interrupt_data->eventfd_ctxs) {
> > >   		kfree(interrupt_data);
> > > +		interrupt_data = NULL;
> > >   		return -ENOMEM;
> > >   	}
> > > @@ -346,6 +347,7 @@ int gasket_interrupt_init(struct gasket_dev *gasket_dev)
> > >   	if (!interrupt_data->interrupt_counts) {
> > >   		kfree(interrupt_data->eventfd_ctxs);
> > >   		kfree(interrupt_data);
> > > +		interrupt_data = NULL;
> > >   		return -ENOMEM;
> > >   	}
> > > -- 
> > > 2.40.1
> > 
> > Also, your tool is wrong, this is not a correct fix at all.
> > 
> > How did you test it?  Why is your tool spitting out incorrect code?  Why
> > are you not verifying it's output before asking others to do so?
> > 
> > Please don't do this anymore, it's wasteful on our side, right?  Please
> > take the time to review existing changes for problems, that would be
> > more useful overall to everyone.
> > 
> > thanks,
> > 
> > greg k-h
> 
> I apologize, there is a mistake. It should've been
> gasket_dev->interrupt_data = NULL istead of interrupt_data = NULL

Which implies that your tools are broken, right?  Please do better
testing before sending anymore patches.

greg k-h