UBUNTU-CVE-2026-43344: Medium severity ubuntu/linux-hwe-edge vulnerability
In the Linux kernel, the following vulnerability has been resolved: perf/x86/intel/uncore: Fix die ID init and look up bugs In snbeppci2phymapinit(), in the nrnodeids > 8 path, uncoredevicetodie() may return -1 when all CPUs associated with the UBOX device are offline. Remove the WARNONONCE(dieid == -1) check for two reasons: - The current code breaks out of the loop. This is incorrect because pcigetdevice() 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 dieid == -1 is expected and should not be treated as an error. Separately, when NUMA is disabled on a NUMA-capable platform, pcibustonode() returns NUMANONODE, causing uncoredevicetodie() to return -1 for all PCI devices. As a result, sprupdatedevicelocation(), used on Intel SPR and EMR, ignores the corresponding PMON units and does not add them to the RB tree. Fix this by using uncorepcibustodieid(), which retrieves topology from the UBOX GIDNIDMAP register and works regardless of whether NUMA is enabled in Linux. This requires snbeppci2phymapinit() to be added in spruncorepciinit(). Keep uncoredevicetodie() only for the nrnodeids > 8 case, where NUMA is expected to be enabled.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
ubuntu/linux-nvidiato a version that resolves this vulnerability.Fixed in 7.0.0-1006.6 - Compensating control
Update the Linux kernel perf/x86/intel/uncore code to use uncore_pcibus_to_dieid() in spr_update_device_location(), retain uncore_device_to_die() only for the nr_node_ids > 8 case, remove the WARN_ON_ONCE(die_id == -1) check, and add snbep_pci2phy_map_init() to spr_uncore_pci_init().