Re: [tip:x86/core 1/1] vmlinux.o: warning: objtool: rcar_pcie_probe+0x13e: no-cfi indirect call!

[Nathan Chancellor <nathan@kernel.org>]

On Fri, Oct 10, 2025 at 09:44:46AM +0200, Peter Zijlstra wrote:
> That's here... and that is indeed broken. Also note how it zeros r11
> right before calling it.
> 
> AFAICT this is:
> 
>         host->phy_init_fn = of_device_get_match_data(dev);
>         err = host->phy_init_fn(host);
> 
> Where it has decided that of_device_get_match_data() *will* return NULL
> and then helpfully emits (*NULL)(); or something like that. And then

Oh duh because it will :)

  $ rg '^(# )?CONFIG_OF' .config
  1528:# CONFIG_OF is not set

which means that of_device_get_match_data() is always NULL:

  static inline const void *of_device_get_match_data(const struct device *dev)
  {
      return NULL;
  }

> forgets to add CFI bits on for extra fun and games.

which means this is another instance of what Sami mentioned happening on
another report of a similar issue

  https://lore.kernel.org/CABCJKue1wCB6jBLYUc-fAEzpyQWHXwbk8R5GBaZCkCao0EQZPA@mail.gmail.com/

which does somewhat make sense because what's the point of setting up
the CFI call if you know nothing can actually make use of it since we
will crash when trying to indirectly call a NULL pointer?

Something like this would avoid this issue then.

Cheers,
Nathan

diff --git a/drivers/pci/controller/pcie-rcar-host.c b/drivers/pci/controller/pcie-rcar-host.c
index 213028052aa5..15514c9c1927 100644
--- a/drivers/pci/controller/pcie-rcar-host.c
+++ b/drivers/pci/controller/pcie-rcar-host.c
@@ -981,7 +981,7 @@ static int rcar_pcie_probe(struct platform_device *pdev)
 		goto err_clk_disable;
 
 	host->phy_init_fn = of_device_get_match_data(dev);
-	err = host->phy_init_fn(host);
+	err = host->phy_init_fn ? host->phy_init_fn(host) : -ENODEV;
 	if (err) {
 		dev_err(dev, "failed to init PCIe PHY\n");
 		goto err_clk_disable;