CVE-2026-43344: perf/x86/intel/uncore: Fix die ID init and look up bugs
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
Event History
Frequently Asked Questions
What is the severity of CVE-2026-43344?
The severity of CVE-2026-43344 is classified as medium due to the potential impact on system stability.
How do I fix CVE-2026-43344?
To fix CVE-2026-43344, update to the latest version of the Linux kernel where the vulnerability has been patched.
Who is affected by CVE-2026-43344?
CVE-2026-43344 affects users running specific versions of the Linux kernel that include the vulnerable code.
What components are involved in CVE-2026-43344?
CVE-2026-43344 involves the perf subsystem and the uncore feature of the x86 architecture in the Linux kernel.
Is CVE-2026-43344 exploitable?
CVE-2026-43344 is not directly classified as remotely exploitable but may lead to system instability, affecting local processes.