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CVE-2026-45919

Full vulnerability record from the local CVENow database.

Description

In the Linux kernel, the following vulnerability has been resolved: sched/rt: Skip currently executing CPU in rto_next_cpu() CPU0 becomes overloaded when hosting a CPU-bound RT task, a non-CPU-bound RT task, and a CFS task stuck in kernel space. When other CPUs switch from RT to non-RT tasks, RT load balancing (LB) is triggered; with HAVE_RT_PUSH_IPI enabled, they send IPIs to CPU0 to drive the execution of rto_push_irq_work_func. During push_rt_task on CPU0, if next_task->prio < rq->donor->prio, resched_curr() sets NEED_RESCHED and after the push operation completes, CPU0 calls rto_next_cpu(). Since only CPU0 is overloaded in this scenario, rto_next_cpu() should ideally return -1 (no further IPI needed). However, multiple CPUs invoking tell_cpu_to_push() during LB increments rd->rto_loop_next. Even when rd->rto_cpu is set to -1, the mismatch between rd->rto_loop and rd->rto_loop_next forces rto_next_cpu() to restart its search from -1. With CPU0 remaining overloaded (satisfying rt_nr_migratory && rt_nr_total > 1), it gets reselected, causing CPU0 to queue irq_work to itself and send self-IPIs repeatedly. As long as CPU0 stays overloaded and other CPUs run pull_rt_tasks(), it falls into an infinite self-IPI loop, which triggers a CPU hardlockup due to continuous self-interrupts. The trigging scenario is as follows: cpu0 cpu1 cpu2 pull_rt_task tell_cpu_to_push <------------irq_work_queue_on rto_push_irq_work_func push_rt_task resched_curr(rq) pull_rt_task rto_next_cpu tell_cpu_to_push <-------------------------- atomic_inc(rto_loop_next) rd->rto_loop != next rto_next_cpu irq_work_queue_on rto_push_irq_work_func Fix redundant self-IPI by filtering the initiating CPU in rto_next_cpu(). This solution has been verified to effectively eliminate spurious self-IPIs and prevent CPU hardlockup scenarios.

Severity
MEDIUM
CVSS score
5.5 (v3.1)
Vulnerability status
Undergoing Analysis
Source identifier
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Published
2026-05-27 14:17:06.790000
Last modified
2026-11-06 16:18:52.047000
View original CVE JSON 
{
  "id": "CVE-2026-45919",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "published": "2026-05-27T14:17:06.790",
  "lastModified": "2026-11-06T16:18:52.047",
  "vulnStatus": "Undergoing Analysis",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "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."
    }
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          "baseScore": 5.5,
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          "attackVector": "LOCAL",
          "attackComplexity": "LOW",
          "privilegesRequired": "LOW",
          "userInteraction": "NONE",
          "scope": "UNCHANGED",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "availabilityImpact": "HIGH"
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          "options": [
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            {
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          "role": "CISA Coordinator",
          "version": "2.0.3"
        }
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  "weaknesses": [
    {
      "source": "[email protected]",
      "type": "Primary",
      "description": [
        {
          "lang": "en",
          "value": "CWE-835"
        }
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