Re: [PATCH] PCI/pwrctl: Do not assume device node presence
From: Manivannan Sadhasivam
Date: Thu Nov 21 2024 - 07:07:25 EST
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@xxxxxxxxx>
> Closes: https://lore.kernel.org/linux-pci/a7b8f84d-efa6-490c-8594-84c1de9a7031@xxxxxxxxx/
> Fixes: cc70852b0962 ("PCI/pwrctl: Ensure that pwrctl drivers are probed before PCI client drivers")
> Cc: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx>
> Cc: Krzysztof Wilczyński <kwilczynski@xxxxxxxxxx>
> Cc: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
> Cc: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxx>
> Cc: stable+noautosel@xxxxxxxxxx # Depends on power supply check
> Signed-off-by: Chen-Yu Tsai <wenst@xxxxxxxxxxxx>
Thanks for the fix!
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx>
- 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
>
--
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