[PATCH v2 RESEND] PCI: fix reference leak in pci_register_host_bridge()

[PATCH v2 RESEND] PCI: fix reference leak in pci_register_host_bridge()

[Ma Ke]

Once device_register() failed, we should call put_device() to
decrement reference count for cleanup. Or it could cause memory leak.

device_register() includes device_add(). As comment of device_add()
says, 'if device_add() succeeds, you should call device_del() when you
want to get rid of it. If device_add() has not succeeded, use only
put_device() to drop the reference count'.

Found by code review.

Cc: stable@vger.kernel.org
Fixes: 37d6a0a6f470 ("PCI: Add pci_register_host_bridge() interface")
Signed-off-by: Ma Ke <make24@iscas.ac.cn>
---
Changes in v2:
- modified the patch description.
---
 drivers/pci/probe.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 246744d8d268..7b1d7ce3a83e 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -1018,8 +1018,10 @@ static int pci_register_host_bridge(struct pci_host_bridge *bridge)
 	name = dev_name(&bus->dev);
 
 	err = device_register(&bus->dev);
-	if (err)
+	if (err) {
+		put_device(&bus->dev);
 		goto unregister;
+	}
 
 	pcibios_add_bus(bus);
 
-- 
2.25.1

Re: [PATCH v2 RESEND] PCI: fix reference leak in pci_register_host_bridge()

[Bjorn Helgaas]

On Tue, Feb 25, 2025 at 10:14:40AM +0800, Ma Ke wrote:
> Once device_register() failed, we should call put_device() to
> decrement reference count for cleanup. Or it could cause memory leak.
> 
> device_register() includes device_add(). As comment of device_add()
> says, 'if device_add() succeeds, you should call device_del() when you
> want to get rid of it. If device_add() has not succeeded, use only
> put_device() to drop the reference count'.
> 
> Found by code review.
> 
> Cc: stable@vger.kernel.org
> Fixes: 37d6a0a6f470 ("PCI: Add pci_register_host_bridge() interface")
> Signed-off-by: Ma Ke <make24@iscas.ac.cn>

Applied to pci/enumeration for v6.15, thanks!

> ---
> Changes in v2:
> - modified the patch description.
> ---
>  drivers/pci/probe.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
> index 246744d8d268..7b1d7ce3a83e 100644
> --- a/drivers/pci/probe.c
> +++ b/drivers/pci/probe.c
> @@ -1018,8 +1018,10 @@ static int pci_register_host_bridge(struct pci_host_bridge *bridge)
>  	name = dev_name(&bus->dev);
>  
>  	err = device_register(&bus->dev);
> -	if (err)
> +	if (err) {
> +		put_device(&bus->dev);
>  		goto unregister;
> +	}
>  
>  	pcibios_add_bus(bus);
>  
> -- 
> 2.25.1
> 

[PATCH v2 RESEND] PCI: fix reference leak in pci_register_host_bridge()

[Ma Ke]

Once device_register() failed, we should call put_device() to
decrement reference count for cleanup. Or it could cause memory leak.

device_register() includes device_add(). As comment of device_add()
says, 'if device_add() succeeds, you should call device_del() when you
want to get rid of it. If device_add() has not succeeded, use only
put_device() to drop the reference count'.

Found by code review.

Cc: stable@vger.kernel.org
Fixes: 37d6a0a6f470 ("PCI: Add pci_register_host_bridge() interface")
Signed-off-by: Ma Ke <make24@iscas.ac.cn>
---
Changes in v2:
- modified the patch description.
---
 drivers/pci/probe.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 246744d8d268..7b1d7ce3a83e 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -1018,8 +1018,10 @@ static int pci_register_host_bridge(struct pci_host_bridge *bridge)
 	name = dev_name(&bus->dev);
 
 	err = device_register(&bus->dev);
-	if (err)
+	if (err) {
+		put_device(&bus->dev);
 		goto unregister;
+	}
 
 	pcibios_add_bus(bus);
 
-- 
2.25.1

Re: [PATCH v2 RESEND] PCI: fix reference leak in pci_register_host_bridge()

[Krzysztof Wilczyński]

Hello,

> Once device_register() failed, we should call put_device() to
> decrement reference count for cleanup. Or it could cause memory leak.
> 
> device_register() includes device_add(). As comment of device_add()
> says, 'if device_add() succeeds, you should call device_del() when you
> want to get rid of it. If device_add() has not succeeded, use only
> put_device() to drop the reference count'.
> 
> Found by code review.

Bjorn took this already, see:

  https://lore.kernel.org/linux-pci/20250227220124.GA19560@bhelgaas

That said, you need to ease on the resends a bit.  We track your patches
and we will get to these eventually.  Please relax a bit, and perhaps focus
your energy here on offering code reviews for other changes, which is
always a great thing to do and helps us a lot. :)

Thank you!

	Krzysztof