RE: [PATCH] PCI: imx6: Avoid dereferencing a NULL clock name

[Hongxing Zhu]

> -----Original Message-----
> From: Rudi Heitbaum <rudi@xxxxxxxxxxxx>
> Sent: Sunday, August 2, 2026 6:55 PM
> To: Hongxing Zhu <hongxing.zhu@xxxxxxx>; Lucas Stach
> <l.stach@xxxxxxxxxxxxxx>
> Cc: Lorenzo Pieralisi <lpieralisi@xxxxxxxxxx>; Krzysztof Wilczyński
> <kwilczynski@xxxxxxxxxx>; Manivannan Sadhasivam <mani@xxxxxxxxxx>; Rob
> Herring <robh@xxxxxxxxxx>; Bjorn Helgaas <bhelgaas@xxxxxxxxxx>; linux-
> pci@xxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; imx@xxxxxxxxxxxxxxx;
> linux-kernel@xxxxxxxxxxxxxxx; stable@xxxxxxxxxxxxxxx; rudi@xxxxxxxxxxxx
> Subject: [PATCH] PCI: imx6: Avoid dereferencing a NULL clock name
> 
> [You don't often get email from rudi@xxxxxxxxxxxx. Learn why this is important
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> 
> of_clk_bulk_get() leaves clk_bulk_data::id as NULL for every clock that has no
> matching entry in "clock-names", which is legal: a node may list more "clocks"
> phandles than it names. The extref scan dereferences that id unconditionally, so
> such a node oopses during probe.
> 
> Check clk_bulk_data::id before dereferencing it.
> 
> Fixes: d8574ce57d76 ("PCI: imx6: Add external reference clock input mode
> support")
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Rudi Heitbaum <rudi@xxxxxxxxxxxx>
Good catch.
This isn't triggered in my daily tests, but the fix is correct.
Thanks for this fix.
Acked-by: Richard Zhu <hongxing.zhu@xxxxxxx>

Best Regards
Richard Zhu
> ---
>  drivers/pci/controller/dwc/pci-imx6.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/pci/controller/dwc/pci-imx6.c
> b/drivers/pci/controller/dwc/pci-imx6.c
> index f7389b5437df..dcdeba1856f7 100644
> --- a/drivers/pci/controller/dwc/pci-imx6.c
> +++ b/drivers/pci/controller/dwc/pci-imx6.c
> @@ -1831,7 +1831,8 @@ static int imx_pcie_probe(struct platform_device
> *pdev)
>                 return dev_err_probe(dev, imx_pcie->num_clks,
>                                      "failed to get clocks\n");
>         for (i = 0; i < imx_pcie->num_clks; i++)
> -               if (strncmp(imx_pcie->clks[i].id, "extref", 6) == 0)
> +               if (imx_pcie->clks[i].id &&
> +                   strncmp(imx_pcie->clks[i].id, "extref", 6) == 0)
>                         imx_pcie->enable_ext_refclk = true;
> 
>         if (imx_check_flag(imx_pcie, IMX_PCIE_FLAG_HAS_PHYDRV)) {
> --
> 2.53.0