Re: [PATCH RFC v5 5/7] ipmi: ls2k: Relax the dependency to its mfd driver

Thank you for your contribution! Sashiko AI review found 1 potential issue(=
s) to consider:

Pre-existing issues:
- [High] Blind dereference of platform device resources without checking if=
 resources exist, leading to a potential NULL pointer dereference.
--

--- Patch [5]: [PATCH RFC v5 5/7] ipmi: ls2k: Relax the dependency to its m=
fd driver ---
commit 41124ab927989929db3ae83837ad0e4e74e88d2e
Author: Miao Wang <[email protected]>

ipmi: ls2k: Relax the dependency to its mfd driver

This commit changes the Kconfig dependency for the Loongson-2K IPMI
interface from select to imply for MFD_LS2K_BMC_CORE. This allows
the IPMI driver to be compiled independently of the MFD driver.

> diff --git a/drivers/char/ipmi/Kconfig b/drivers/char/ipmi/Kconfig
> index 669f760001974..f456e3e894169 100644
> --- a/drivers/char/ipmi/Kconfig
> +++ b/drivers/char/ipmi/Kconfig
[ ... ]
> @@ -87,7 +87,7 @@ config IPMI_IPMB
>  config IPMI_LS2K
>  	bool 'Loongson-2K IPMI interface'
>  	depends on LOONGARCH
> -	select MFD_LS2K_BMC_CORE
> +	imply MFD_LS2K_BMC_CORE

[Severity: High]
This is a pre-existing issue and was not introduced by the patch under
review, but since this change allows the IPMI driver to probe independently
of the MFD driver, I noticed a potential regression with resource handling.

Looking at ipmi_ls2k_probe() in drivers/char/ipmi/ipmi_si_ls2k.c:

    io.addr_data =3D pdev->resource[0].start;
    io.regspacing =3D resource_size(&pdev->resource[0]);

Does this code blindly dereference the platform device resources without
checking if they exist?

If the platform device is instantiated without resources (such as manually
via sysfs, or due to a misconfigured MFD core or device tree), would
pdev->resource be NULL and cause a kernel panic?

Would it be safer to verify pdev->num_resources > 0 or use
platform_get_resource() before accessing pdev->resource[0]?

>  	help
>  	  Provides a driver for Loongson-2K IPMI interfaces.

--=20
Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20260804-ls2kbmc-mo=
[email protected]?part=3D5