CVE-2026-43344perf/x86/intel/uncore: Fix die ID init and look up bugs

Official description

In the Linux kernel, the following vulnerability has been resolved: perf/x86/intel/uncore: Fix die ID init and look up bugs In snbep_pci2phy_map_init(), in the nr_node_ids > 8 path, uncore_device_to_die() may return -1 when all CPUs associated with the UBOX device are offline. Remove the WARN_ON_ONCE(die_id == -1) check for two reasons: - The current code breaks out of the loop. This is incorrect because pci_get_device() does not guarantee iteration in domain or bus order, so additional UBOX devices may be skipped during the scan. - Returning -EINVAL is incorrect, since marking offline buses with die_id == -1 is expected and should not be treated as an error. Separately, when NUMA is disabled on a NUMA-capable platform, pcibus_to_node() returns NUMA_NO_NODE, causing uncore_device_to_die() to return -1 for all PCI devices. As a result, spr_update_device_location(), used on Intel SPR and EMR, ignores the corresponding PMON units and does not add them to the RB tree. Fix this by using uncore_pcibus_to_dieid(), which retrieves topology from the UBOX GIDNIDMAP register and works regardless of whether NUMA is enabled in Linux. This requires snbep_pci2phy_map_init() to be added in spr_uncore_pci_init(). Keep uncore_device_to_die() only for the nr_node_ids > 8 case, where NUMA is expected to be enabled.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/4eb511275e37c580156e787baab5232aeb0bfea0
• https://git.kernel.org/stable/c/184870af0e73f8ea2577c751fa098681465249f2
• https://git.kernel.org/stable/c/bdb35811ff41a1678620a407056b6372f350028a
• https://git.kernel.org/stable/c/c79ef3342632e71ac8612a2a1cc17ac84dd258b4
• https://git.kernel.org/stable/c/6a5dc3ee97581da2907fc7acd62853f07184de67
• https://git.kernel.org/stable/c/a16d1ec4dd0cdcf689f324adde6067083bce9099