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CVE-2026-43344

perf/x86/intel/uncore: Fix die ID init and look up bugs PUBLISHED

Description (CNA)

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 (CNA)

Vendor / productVersions
Linux / Linuxaffected 9a7832ce3d920426a36cdd78eda4b3568d4d09e3 before 184870af0e73f8ea2577c751fa098681465249f2; affected 9a7832ce3d920426a36cdd78eda4b3568d4d09e3 before bdb35811ff41a1678620a407056b6372f350028a; affected 9a7832ce3d920426a36cdd78eda4b3568d4d09e3 before c79ef3342632e71ac8612a2a1cc17ac84dd258b4; affected 9a7832ce3d920426a36cdd78eda4b3568d4d09e3 before 6a5dc3ee97581da2907fc7acd62853f07184de67; affected 9a7832ce3d920426a36cdd78eda4b3568d4d09e3 before a16d1ec4dd0cdcf689f324adde6067083bce9099
Linux / Linuxaffected 5.12; unaffected 0 before 5.12; unaffected 6.6.157 through 6.6.*; unaffected 6.12.109 through 6.12.*; unaffected 6.18.50 through 6.18.*; unaffected 6.19.14 through 6.19.*; unaffected 7.0 through *

CWE

No CWE identifiers supplied.

References