Re: [PATCH] tty: vt: consolemap: Add missing kfree() in con_do_clear_unimap()

[Jiri Slaby]

Hi,

On 09. 03. 22, 13:34, 聂江磊 wrote:
> I found this bug by using clang static analyse checkers. I found that 
> function con_release_unimap() is only called in this 
> file(drivers/tty/vt/consolemap.c b/drivers/tty/vt/consolemap.c). There 
> are totally 5 times that con_release_unimap() is called
> (line 430, 466, 522, 599, 673) while con_release_unimap() is not 
> followed by kfree() only in line 522. So I think it is a bug
> and make this patch.
>
>
> At 2022-03-03 10:06:30, "Jianglei Nie" <niejianglei2021@xxxxxxx> wrote:
> > We should free p after con_release_unimap(p) like the call points of
> > con_release_unimap() do in the same file.

But this one does not free it on purpose, right? See below.

> > This patch adds the missing kfree() after con_release_unimap(p).
> >
> > Signed-off-by: Jianglei Nie <niejianglei2021@xxxxxxx>
> > ---
> > drivers/tty/vt/consolemap.c | 1 +
> > 1 file changed, 1 insertion(+)
> >
> > diff --git a/drivers/tty/vt/consolemap.c b/drivers/tty/vt/consolemap.c
> > index d815ac98b39e..5279c3d27720 100644
> > --- a/drivers/tty/vt/consolemap.c
> > +++ b/drivers/tty/vt/consolemap.c
> > @@ -520,6 +520,7 @@ static int con_do_clear_unimap(struct vc_data *vc)
> > 		p->refcount++;
> > 		p->sum = 0;
> > 		con_release_unimap(p);
> > +		kfree(p);

You've just broken con_set_unimap(), or do I miss something?

> > 	}
> > 	return 0;
> > }


--
js
suse labs