platform/x86/amd/pmc: Propagate SMU errors and validate S2D address

Summary

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().

Timeline

1. Sep 11, 2026, 7:43 PM UTCCVE published
2. Oct 21, 2026, 12:47 PM UTCRecord last updated

Affected versions

• Linux Linux

  From 3d7d407dfb05b257e15cb0c6b056428a4a8c2e5d · fixed in 85ef9d4c384c1d143c51580933674d94dba3b8d9; From 3d7d407dfb05b257e15cb0c6b056428a4a8c2e5d · fixed in 638e1ca5d4e2b4fdbb209db64926d013b34f3b79; From 3d7d407dfb05b257e15cb0c6b056428a4a8c2e5d · fixed in 8178f59d76570b152d836bde07f5997f15861f04; From 3d7d407dfb05b257e15cb0c6b056428a4a8c2e5d · fixed in 775d4cde1f9737796ce7d8393521e9e8c5b49891; From 3d7d407dfb05b257e15cb0c6b056428a4a8c2e5d · fixed in 0225c1d637687b03726f00ac65b6def843d2c464

• Linux Linux

  5.18

• KernelLinux

  From 5.18.0 · fixed in 6.6.160; From 6.7.0 · fixed in 6.12.112; From 6.13.0 · fixed in 6.18.50; From 6.19.0 · fixed in 7.2.4

References 5