Infinite Retry Loop in Linux Kernel Driver Affects System Performance

CVE-2026-99251

What is CVE-2026-99251?

A vulnerability in the Linux kernel's hv driver introduces an infinite retry loop in the init_vp_index() function. This occurs when CPUs from a certain node are stripped out due to their presence in the allocated cpumask or their absence in the HK_TYPE_MANAGED_IRQ housekeeping cpumask. If no CPUs remain, this leads to a retry that can result in a loop without successful completion. Although rare, this issue can significantly impact system performance. The fix involves modifying the retry logic to skip NUMA nodes lacking housekeeping CPUs and ensuring that the outer loop is only executed when at least one online housekeeping CPU is available.

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