{"cve":"CVE-2026-45919","nvd":{"published":"2026-05-27T14:17:06.790","modified":"2026-06-24T17:22:38.663","status":"Undergoing Analysis","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nsched/rt: Skip currently executing CPU in rto_next_cpu()\n\nCPU0 becomes overloaded when hosting a CPU-bound RT task, a non-CPU-bound\nRT task, and a CFS task stuck in kernel space. When other CPUs switch from\nRT to non-RT tasks, RT load balancing (LB) is triggered; with\nHAVE_RT_PUSH_IPI enabled, they send IPIs to CPU0 to drive the execution\nof rto_push_irq_work_func. During push_rt_task on CPU0,\nif next_task->prio < rq->donor->prio, resched_curr() sets NEED_RESCHED\nand after the push operation completes, CPU0 calls rto_next_cpu().\nSince only CPU0 is overloaded in this scenario, rto_next_cpu() should\nideally return -1 (no further IPI needed).\n\nHowever, multiple CPUs invoking tell_cpu_to_push() during LB increments\nrd->rto_loop_next. Even when rd->rto_cpu is set to -1, the mismatch between\nrd->rto_loop and rd->rto_loop_next forces rto_next_cpu() to restart its\nsearch from -1. With CPU0 remaining overloaded (satisfying rt_nr_migratory\n&& rt_nr_total > 1), it gets reselected, causing CPU0 to queue irq_work to\nitself and send self-IPIs repeatedly. As long as CPU0 stays overloaded and\nother CPUs run pull_rt_tasks(), it falls into an infinite self-IPI loop,\nwhich triggers a CPU hardlockup due to continuous self-interrupts.\n\nThe trigging scenario is as follows:\n\n         cpu0                      cpu1                    cpu2\n                                pull_rt_task\n                              tell_cpu_to_push\n                 <------------irq_work_queue_on\nrto_push_irq_work_func\n       push_rt_task\n    resched_curr(rq)                                   pull_rt_task\n    rto_next_cpu                                     tell_cpu_to_push\n                      <-------------------------- atomic_inc(rto_loop_next)\nrd->rto_loop != next\n     rto_next_cpu\n   irq_work_queue_on\nrto_push_irq_work_func\n\nFix redundant self-IPI by filtering the initiating CPU in rto_next_cpu().\nThis solution has been verified to effectively eliminate spurious self-IPIs\nand prevent CPU hardlockup scenarios.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","score":5.5},"cwes":["CWE-835"],"references":["https://git.kernel.org/stable/c/16ca9f3117e9a294646c897daf08a5ab546c711b","https://git.kernel.org/stable/c/3b3c672a66db3de3b40f8a7057864bc1f874ede3","https://git.kernel.org/stable/c/52aeb1e07ec223caf212f036817976c98d2aa250","https://git.kernel.org/stable/c/8ad5577b2d4acfd83f03d97a0aece2d18aac5f07","https://git.kernel.org/stable/c/94894c9c477e53bcea052e075c53f89df3d2a33e"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T22:36:28.938604137+00:00"},"epss":{"cve":"CVE-2026-45919","score":0.0013,"percentile":0.02646,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}