CVE-2025-40157

In the Linux kernel, the following vulnerability has been resolved:

EDAC/i10nm: Skip DIMM enumeration on a disabled memory controller

When loading the i10nm_edac driver on some Intel Granite Rapids servers, a call trace may appear as follows:

UBSAN: shift-out-of-bounds in drivers/edac/skxcommon.c:453:16 shift exponent -66 is negative ... _ubsanhandleshiftoutofbounds+0x1e3/0x390 skxgetdimminfo.cold+0x47/0xd40 [skxedaccommon] i10nmgetdimmconfig+0x23e/0x390 [i10nmedac] skxregistermci+0x159/0x220 [skxedaccommon] i10nminit+0xcb0/0x1ff0 [i10nmedac] ...

This occurs because some BIOS may disable a memory controller if there aren't any memory DIMMs populated on this memory controller. The DIMMMTR register of this disabled memory controller contains the invalid value ~0, resulting in the call trace above.

Fix this call trace by skipping DIMM enumeration on a disabled memory controller.