[PATCH] tty_port: Fix refcounting leak in tty_port_tty_hangup()

[PATCH] tty_port: Fix refcounting leak in tty_port_tty_hangup()

[Gianluca Anzolin]

The function tty_port_tty_hangup() could leak a reference to the tty_struct:

        struct tty_struct *tty = tty_port_tty_get(port);

        if (tty && (!check_clocal || !C_CLOCAL(tty))) {
                tty_hangup(tty);
                tty_kref_put(tty);
        }

If tty != NULL and the second condition is false we never call tty_kref_put and
the reference is leaked.

Fix by always calling tty_kref_put() which accepts a NULL argument.

The patch fixes a regression introduced by commit aa27a094.

Acked-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Signed-off-by: Gianluca Anzolin <gianluca@sottospazio.it>
---
 drivers/tty/tty_port.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/tty/tty_port.c b/drivers/tty/tty_port.c
index 121aeb9..f597e88 100644
--- a/drivers/tty/tty_port.c
+++ b/drivers/tty/tty_port.c
@@ -256,10 +256,9 @@ void tty_port_tty_hangup(struct tty_port *port, bool check_clocal)
 {
 	struct tty_struct *tty = tty_port_tty_get(port);
 
-	if (tty && (!check_clocal || !C_CLOCAL(tty))) {
+	if (tty && (!check_clocal || !C_CLOCAL(tty)))
 		tty_hangup(tty);
-		tty_kref_put(tty);
-	}
+	tty_kref_put(tty);
 }
 EXPORT_SYMBOL_GPL(tty_port_tty_hangup);
 
-- 
1.8.3.3

Re: [PATCH] tty_port: Fix refcounting leak in tty_port_tty_hangup()

[Jiri Slaby]

On 07/25/2013 07:26 AM, Gianluca Anzolin wrote:
> The function tty_port_tty_hangup() could leak a reference to the tty_struct:
> 
>         struct tty_struct *tty = tty_port_tty_get(port);
> 
>         if (tty && (!check_clocal || !C_CLOCAL(tty))) {
>                 tty_hangup(tty);
>                 tty_kref_put(tty);
>         }
> 
> If tty != NULL and the second condition is false we never call tty_kref_put and
> the reference is leaked.
> 
> Fix by always calling tty_kref_put() which accepts a NULL argument.
> 
> The patch fixes a regression introduced by commit aa27a094.
> 
> Acked-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
> Signed-off-by: Gianluca Anzolin <gianluca@sottospazio.it>

Acked-by: Jiri Slaby <jslaby@suse.cz>

Thanks for the fix.

> ---
>  drivers/tty/tty_port.c | 5 ++---
>  1 file changed, 2 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/tty/tty_port.c b/drivers/tty/tty_port.c
> index 121aeb9..f597e88 100644
> --- a/drivers/tty/tty_port.c
> +++ b/drivers/tty/tty_port.c
> @@ -256,10 +256,9 @@ void tty_port_tty_hangup(struct tty_port *port, bool check_clocal)
>  {
>  	struct tty_struct *tty = tty_port_tty_get(port);
>  
> -	if (tty && (!check_clocal || !C_CLOCAL(tty))) {
> +	if (tty && (!check_clocal || !C_CLOCAL(tty)))
>  		tty_hangup(tty);
> -		tty_kref_put(tty);
> -	}
> +	tty_kref_put(tty);
>  }
>  EXPORT_SYMBOL_GPL(tty_port_tty_hangup);
>  
> 


-- 
js
suse labs

Re: [PATCH] tty_port: Fix refcounting leak in tty_port_tty_hangup()

[Gianluca Anzolin]

On Thu, Jul 25, 2013 at 08:26:45AM +0200, Jiri Slaby wrote:
> On 07/25/2013 07:26 AM, Gianluca Anzolin wrote:
> > The function tty_port_tty_hangup() could leak a reference to the tty_struct:
> > 
> >         struct tty_struct *tty = tty_port_tty_get(port);
> > 
> >         if (tty && (!check_clocal || !C_CLOCAL(tty))) {
> >                 tty_hangup(tty);
> >                 tty_kref_put(tty);
> >         }
> > 
> > If tty != NULL and the second condition is false we never call tty_kref_put and
> > the reference is leaked.
> > 
> > Fix by always calling tty_kref_put() which accepts a NULL argument.
> > 
> > The patch fixes a regression introduced by commit aa27a094.
> > 
> > Acked-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
> > Signed-off-by: Gianluca Anzolin <gianluca@sottospazio.it>
> 
> Acked-by: Jiri Slaby <jslaby@suse.cz>
> 
> Thanks for the fix.
> 

Hi,

I sent this morning a newer fix changed following the instructions of Peter
Hurley. Could you apply that fix instead?

Thank you,

Gianluca

Re: [PATCH] tty_port: Fix refcounting leak in tty_port_tty_hangup()

[Gianluca Anzolin]

On Thu, Jul 25, 2013 at 10:14:36AM +0200, Gianluca Anzolin wrote:
> On Thu, Jul 25, 2013 at 08:26:45AM +0200, Jiri Slaby wrote:
> > On 07/25/2013 07:26 AM, Gianluca Anzolin wrote:
> > > The function tty_port_tty_hangup() could leak a reference to the tty_struct:
> > > 
> > >         struct tty_struct *tty = tty_port_tty_get(port);
> > > 
> > >         if (tty && (!check_clocal || !C_CLOCAL(tty))) {
> > >                 tty_hangup(tty);
> > >                 tty_kref_put(tty);
> > >         }
> > > 
> > > If tty != NULL and the second condition is false we never call tty_kref_put and
> > > the reference is leaked.
> > > 
> > > Fix by always calling tty_kref_put() which accepts a NULL argument.
> > > 
> > > The patch fixes a regression introduced by commit aa27a094.
> > > 
> > > Acked-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
> > > Signed-off-by: Gianluca Anzolin <gianluca@sottospazio.it>
> > 
> > Acked-by: Jiri Slaby <jslaby@suse.cz>
> > 
> > Thanks for the fix.
> > 
> 
> Hi,
> 
> I sent this morning a newer fix changed following the instructions of Peter
> Hurley. Could you apply that fix instead?
> 
> Thank you,
> 
> Gianluca

Disregard that, that one was the right fix.

Thanks,
Gianluca