CVE-2026-81016platform/x86/amd/pmc: Propagate SMU errors and validate S2D address

Official description

In the Linux kernel, the following vulnerability has been resolved: platform/x86/amd/pmc: Propagate SMU errors and validate S2D address amd_stb_s2d_init() discards the return value of several S2D SMU commands. When the SMU refuses a command (e.g. "SMU cmd failed. err: 0xff") the failure is only noticed indirectly - if at all - and reported as -EIO, masking the real error. More seriously, the S2D_PHYS_ADDR_LOW/HIGH return values are ignored, so on failure phys_addr_low/hi are left uninitialised and the assembled address is passed straight to devm_ioremap(). When the SMU leaves them at zero this maps physical address 0 and trips the ioremap-on-RAM warning: amd_pmc AMDI000B:00: SMU cmd failed. err: 0xff ioremap on RAM at 0x0000000000000000 - 0x0000000000ffffff WARNING: CPU: 13 PID: 4592 at arch/x86/mm/ioremap.c:... Check the return value of each SMU command and propagate it, and reject a zero physical address before calling devm_ioremap().

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/646cdcc6c7594d8ad81577b2cb05276a927edc28
• https://git.kernel.org/stable/c/85ef9d4c384c1d143c51580933674d94dba3b8d9
• https://git.kernel.org/stable/c/638e1ca5d4e2b4fdbb209db64926d013b34f3b79
• https://git.kernel.org/stable/c/8178f59d76570b152d836bde07f5997f15861f04
• https://git.kernel.org/stable/c/775d4cde1f9737796ce7d8393521e9e8c5b49891
• https://git.kernel.org/stable/c/0225c1d637687b03726f00ac65b6def843d2c464