diff mbox series

PCI/pwrctl: Do not assume device node presence

Message ID 20241121094020.3679787-1-wenst@chromium.org (mailing list archive)
State New
Headers show
Series PCI/pwrctl: Do not assume device node presence | expand

Commit Message

Chen-Yu Tsai Nov. 21, 2024, 9:40 a.m. UTC
A PCI device normally does not have a device node, since the bus is
fully enumerable. Assuming that a device node is presence is likely
bad.

The newly added pwrctl code assumes such and crashes with a NULL
pointer dereference. Besides that, of_find_device_by_node(NULL)
is likely going to return some random device.

Reported-by: Klara Modin <klarasmodin@gmail.com>
Closes: https://lore.kernel.org/linux-pci/a7b8f84d-efa6-490c-8594-84c1de9a7031@gmail.com/
Fixes: cc70852b0962 ("PCI/pwrctl: Ensure that pwrctl drivers are probed before PCI client drivers")
Cc: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Cc: Krzysztof Wilczyński <kwilczynski@kernel.org>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Cc: stable+noautosel@kernel.org         # Depends on power supply check
Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>
---
 drivers/pci/bus.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Bartosz Golaszewski Nov. 21, 2024, 10:23 a.m. UTC | #1
On Thu, Nov 21, 2024 at 10:40 AM Chen-Yu Tsai <wenst@chromium.org> wrote:
>
> A PCI device normally does not have a device node, since the bus is
> fully enumerable. Assuming that a device node is presence is likely

s/presence/present/

> bad.
>
> The newly added pwrctl code assumes such and crashes with a NULL
> pointer dereference. Besides that, of_find_device_by_node(NULL)
> is likely going to return some random device.
>
> Reported-by: Klara Modin <klarasmodin@gmail.com>
> Closes: https://lore.kernel.org/linux-pci/a7b8f84d-efa6-490c-8594-84c1de9a7031@gmail.com/
> Fixes: cc70852b0962 ("PCI/pwrctl: Ensure that pwrctl drivers are probed before PCI client drivers")
> Cc: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
> Cc: Krzysztof Wilczyński <kwilczynski@kernel.org>
> Cc: Bjorn Helgaas <bhelgaas@google.com>
> Cc: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
> Cc: stable+noautosel@kernel.org         # Depends on power supply check
> Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>
> ---
>  drivers/pci/bus.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/pci/bus.c b/drivers/pci/bus.c
> index 98910bc0fcc4..eca72e0c3b6c 100644
> --- a/drivers/pci/bus.c
> +++ b/drivers/pci/bus.c
> @@ -405,7 +405,7 @@ void pci_bus_add_device(struct pci_dev *dev)
>          * before PCI client drivers.
>          */
>         pdev = of_find_device_by_node(dn);
> -       if (pdev && of_pci_supply_present(dn)) {
> +       if (dn && pdev && of_pci_supply_present(dn)) {
>                 if (!device_link_add(&dev->dev, &pdev->dev,
>                                      DL_FLAG_AUTOREMOVE_CONSUMER))
>                         pci_err(dev, "failed to add device link to power control device %s\n",
> --
> 2.47.0.338.g60cca15819-goog
>
>

Reviewed-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Klara Modin Nov. 21, 2024, 10:42 a.m. UTC | #2
On 2024-11-21 10:40, Chen-Yu Tsai wrote:
> A PCI device normally does not have a device node, since the bus is
> fully enumerable. Assuming that a device node is presence is likely
> bad.
> 
> The newly added pwrctl code assumes such and crashes with a NULL
> pointer dereference. Besides that, of_find_device_by_node(NULL)
> is likely going to return some random device.
> 
> Reported-by: Klara Modin <klarasmodin@gmail.com>
> Closes: https://lore.kernel.org/linux-pci/a7b8f84d-efa6-490c-8594-84c1de9a7031@gmail.com/
> Fixes: cc70852b0962 ("PCI/pwrctl: Ensure that pwrctl drivers are probed before PCI client drivers")
> Cc: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
> Cc: Krzysztof Wilczyński <kwilczynski@kernel.org>
> Cc: Bjorn Helgaas <bhelgaas@google.com>
> Cc: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
> Cc: stable+noautosel@kernel.org         # Depends on power supply check
> Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>
> ---
>   drivers/pci/bus.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/pci/bus.c b/drivers/pci/bus.c
> index 98910bc0fcc4..eca72e0c3b6c 100644
> --- a/drivers/pci/bus.c
> +++ b/drivers/pci/bus.c
> @@ -405,7 +405,7 @@ void pci_bus_add_device(struct pci_dev *dev)
>   	 * before PCI client drivers.
>   	 */
>   	pdev = of_find_device_by_node(dn);
> -	if (pdev && of_pci_supply_present(dn)) {
> +	if (dn && pdev && of_pci_supply_present(dn)) {
>   		if (!device_link_add(&dev->dev, &pdev->dev,
>   				     DL_FLAG_AUTOREMOVE_CONSUMER))
>   			pci_err(dev, "failed to add device link to power control device %s\n",

Thanks for the fix,
Tested-by: Klara Modin <klarasmodin@gmail.com>
Manivannan Sadhasivam Nov. 21, 2024, 12:06 p.m. UTC | #3
On Thu, Nov 21, 2024 at 05:40:19PM +0800, Chen-Yu Tsai wrote:
> A PCI device normally does not have a device node, since the bus is
> fully enumerable. Assuming that a device node is presence is likely
> bad.
> 

I missed the fact that NULL ptr check is removed from of_pci_supply_present().

> The newly added pwrctl code assumes such and crashes with a NULL
> pointer dereference. Besides that, of_find_device_by_node(NULL)
> is likely going to return some random device.
> 

Yeah, good catch.

> Reported-by: Klara Modin <klarasmodin@gmail.com>
> Closes: https://lore.kernel.org/linux-pci/a7b8f84d-efa6-490c-8594-84c1de9a7031@gmail.com/
> Fixes: cc70852b0962 ("PCI/pwrctl: Ensure that pwrctl drivers are probed before PCI client drivers")
> Cc: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
> Cc: Krzysztof Wilczyński <kwilczynski@kernel.org>
> Cc: Bjorn Helgaas <bhelgaas@google.com>
> Cc: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
> Cc: stable+noautosel@kernel.org         # Depends on power supply check
> Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>

Thanks for the fix!

Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

- Mani

> ---
>  drivers/pci/bus.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/pci/bus.c b/drivers/pci/bus.c
> index 98910bc0fcc4..eca72e0c3b6c 100644
> --- a/drivers/pci/bus.c
> +++ b/drivers/pci/bus.c
> @@ -405,7 +405,7 @@ void pci_bus_add_device(struct pci_dev *dev)
>  	 * before PCI client drivers.
>  	 */
>  	pdev = of_find_device_by_node(dn);
> -	if (pdev && of_pci_supply_present(dn)) {
> +	if (dn && pdev && of_pci_supply_present(dn)) {
>  		if (!device_link_add(&dev->dev, &pdev->dev,
>  				     DL_FLAG_AUTOREMOVE_CONSUMER))
>  			pci_err(dev, "failed to add device link to power control device %s\n",
> -- 
> 2.47.0.338.g60cca15819-goog
>
diff mbox series

Patch

diff --git a/drivers/pci/bus.c b/drivers/pci/bus.c
index 98910bc0fcc4..eca72e0c3b6c 100644
--- a/drivers/pci/bus.c
+++ b/drivers/pci/bus.c
@@ -405,7 +405,7 @@  void pci_bus_add_device(struct pci_dev *dev)
 	 * before PCI client drivers.
 	 */
 	pdev = of_find_device_by_node(dn);
-	if (pdev && of_pci_supply_present(dn)) {
+	if (dn && pdev && of_pci_supply_present(dn)) {
 		if (!device_link_add(&dev->dev, &pdev->dev,
 				     DL_FLAG_AUTOREMOVE_CONSUMER))
 			pci_err(dev, "failed to add device link to power control device %s\n",