serial: core: fix OF node leak

[PATCH] serial: core: fix OF node leak

Posted by Johan Hovold 3 months ago

Make sure to drop the OF node reference taken when initialising the
control and port devices when the devices are later released.

Fixes: d36f0e9a0002 ("serial: core: restore of_node information in sysfs")
Cc: Aidan Stewart <astewart@tektelic.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/tty/serial/serial_base_bus.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/tty/serial/serial_base_bus.c b/drivers/tty/serial/serial_base_bus.c
index cb3b127b06b6..22749ab0428a 100644
--- a/drivers/tty/serial/serial_base_bus.c
+++ b/drivers/tty/serial/serial_base_bus.c
@@ -13,6 +13,7 @@
 #include <linux/device.h>
 #include <linux/idr.h>
 #include <linux/module.h>
+#include <linux/of.h>
 #include <linux/serial_core.h>
 #include <linux/slab.h>
 #include <linux/spinlock.h>
@@ -93,6 +94,7 @@ static void serial_base_ctrl_release(struct device *dev)
 {
 	struct serial_ctrl_device *ctrl_dev = to_serial_base_ctrl_device(dev);
 
+	of_node_put(dev->of_node);
 	kfree(ctrl_dev);
 }
 
@@ -140,6 +142,7 @@ static void serial_base_port_release(struct device *dev)
 {
 	struct serial_port_device *port_dev = to_serial_base_port_device(dev);
 
+	of_node_put(dev->of_node);
 	kfree(port_dev);
 }
 
-- 
2.49.0

Re: [PATCH] serial: core: fix OF node leak

Posted by Aidan Stewart 3 months ago

Hi Johan,

On Tue, 2025-07-08 at 10:58 +0200, Johan Hovold wrote:
> 
> 
> CAUTION: This email originated from outside the organization. Do not
> click links or open attachments unless you recognize the sender and know
> the content is safe.
> 
> 
> 
> Make sure to drop the OF node reference taken when initialising the
> control and port devices when the devices are later released.
> 
> Fixes: d36f0e9a0002 ("serial: core: restore of_node information in
> sysfs")
> Cc: Aidan Stewart <astewart@tektelic.com>
> Signed-off-by: Johan Hovold <johan@kernel.org>
> ---
>  drivers/tty/serial/serial_base_bus.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/tty/serial/serial_base_bus.c
> b/drivers/tty/serial/serial_base_bus.c
> index cb3b127b06b6..22749ab0428a 100644
> --- a/drivers/tty/serial/serial_base_bus.c
> +++ b/drivers/tty/serial/serial_base_bus.c
> @@ -13,6 +13,7 @@
>  #include <linux/device.h>
>  #include <linux/idr.h>
>  #include <linux/module.h>
> +#include <linux/of.h>
>  #include <linux/serial_core.h>
>  #include <linux/slab.h>
>  #include <linux/spinlock.h>
> @@ -93,6 +94,7 @@ static void serial_base_ctrl_release(struct device
> *dev)
>  {
>         struct serial_ctrl_device *ctrl_dev =
> to_serial_base_ctrl_device(dev);
> 
> +       of_node_put(dev->of_node);
>         kfree(ctrl_dev);
>  }
> 
> @@ -140,6 +142,7 @@ static void serial_base_port_release(struct device
> *dev)
>  {
>         struct serial_port_device *port_dev =
> to_serial_base_port_device(dev);
> 
> +       of_node_put(dev->of_node);
>         kfree(port_dev);
>  }
> 
> --
> 2.49.0
Thanks for the fix. I think this also needs to go into -stable, as the
previous changes have already landed there (6.12.36 and 6.15.5).

Aidan

Re: [PATCH] serial: core: fix OF node leak

Posted by Johan Hovold 3 months ago

On Tue, Jul 08, 2025 at 01:37:45PM +0000, Aidan Stewart wrote:
> On Tue, 2025-07-08 at 10:58 +0200, Johan Hovold wrote:

> > Make sure to drop the OF node reference taken when initialising the
> > control and port devices when the devices are later released.
> > 
> > Fixes: d36f0e9a0002 ("serial: core: restore of_node information in
> > sysfs")
> > Cc: Aidan Stewart <astewart@tektelic.com>
> > Signed-off-by: Johan Hovold <johan@kernel.org>

> Thanks for the fix. I think this also needs to go into -stable, as the
> previous changes have already landed there (6.12.36 and 6.15.5).

I left out the stable tag on purpose since this leak should not cause
trouble as, for example, these devices are typically registered at boot
and never deregistered.

It fixes an issue introduced in rc4 so it should preferably still go
into 6.16-final, though.

Johan

Re: [PATCH] serial: core: fix OF node leak

Posted by Greg Kroah-Hartman 3 months ago

On Tue, Jul 08, 2025 at 05:23:38PM +0200, Johan Hovold wrote:
> On Tue, Jul 08, 2025 at 01:37:45PM +0000, Aidan Stewart wrote:
> > On Tue, 2025-07-08 at 10:58 +0200, Johan Hovold wrote:
> 
> > > Make sure to drop the OF node reference taken when initialising the
> > > control and port devices when the devices are later released.
> > > 
> > > Fixes: d36f0e9a0002 ("serial: core: restore of_node information in
> > > sysfs")
> > > Cc: Aidan Stewart <astewart@tektelic.com>
> > > Signed-off-by: Johan Hovold <johan@kernel.org>
> 
> > Thanks for the fix. I think this also needs to go into -stable, as the
> > previous changes have already landed there (6.12.36 and 6.15.5).
> 
> I left out the stable tag on purpose since this leak should not cause
> trouble as, for example, these devices are typically registered at boot
> and never deregistered.
> 
> It fixes an issue introduced in rc4 so it should preferably still go
> into 6.16-final, though.

Ok, will get this merged, thanks!

greg k-h