perf/x86/intel/uncore: Fix uncore_box ref/unref ordering

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-93181
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-17 17:18:14 UTC
Updated2026-09-17 17:18:14 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: perf/x86/intel/uncore: Fix uncore_box ref/unref ordering In uncore_event_cpu_online(), uncore_box_ref() was called before uncore_change_context(). uncore_box_ref() gates on box->cpu >= 0, but box->cpu is still -1 at that point because uncore_change_context() has not run yet. As a result, the box is never initialized on the first CPU to come online in a die, leaving it permanently uninitialized in the single-CPU-per-die case. Thus, box->refcnt is one count below the true value, and in the CPU offline path, the box will be torn down on the second-to-last CPU. In uncore_event_cpu_offline(), uncore_box_unref() was called after uncore_change_context(), so box->cpu is already -1 when the collector CPU goes offline, which prevents it from tearing down the box. Fix by swapping the call order in both paths so that uncore_box_{ref,unref}() runs at the point where box->cpu reflects the correct context. Move allocate_boxes() out of uncore_box_ref() to enable this reordering.

Risk And Classification

EPSS: 0.001890000 probability, percentile 0.088300000 (date 2026-09-18)

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected c74443d92f68f07c03ae242ced554b749e6c6736 64aa1bb4017d598828c6d8cd718f43daf2a83375 git Not specified
CNA Linux Linux affected c74443d92f68f07c03ae242ced554b749e6c6736 174f0582e38abe03b88e15f04bfe58490f88cb19 git Not specified
CNA Linux Linux affected 6.11 Not specified
CNA Linux Linux unaffected 6.11 semver Not specified
CNA Linux Linux unaffected 7.2.6 7.2.* semver Not specified
CNA Linux Linux unaffected 7.3-rc1 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/174f0582e38abe03b88e15f04bfe58490f88cb19 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/64aa1bb4017d598828c6d8cd718f43daf2a83375 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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