{"id":"CVE-2026-45919","title":"sched/rt: Skip currently executing CPU in rto_next_cpu()","summary":"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 ker…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= 4bdced5c9a2922521e325896a7bbbf0132c94e56 < d57d0746276a88ea43a2cc62b849fd8a95e32e41","Linux >= 4bdced5c9a2922521e325896a7bbbf0132c94e56 < 3b3c672a66db3de3b40f8a7057864bc1f874ede3","Linux >= 4bdced5c9a2922521e325896a7bbbf0132c94e56 < 16ca9f3117e9a294646c897daf08a5ab546c711b","Linux >= 4bdced5c9a2922521e325896a7bbbf0132c94e56 < 8ad5577b2d4acfd83f03d97a0aece2d18aac5f07","Linux >= 4bdced5c9a2922521e325896a7bbbf0132c94e56 < a6a73403733e86748421f2eeaf028c85683ef896","Linux >= 4bdced5c9a2922521e325896a7bbbf0132c94e56 < 52aeb1e07ec223caf212f036817976c98d2aa250","Linux >= 4bdced5c9a2922521e325896a7bbbf0132c94e56 < 9f25edc5a20cb52a5abbf25f0724bb4732b81801","Linux >= 4bdced5c9a2922521e325896a7bbbf0132c94e56 < 94894c9c477e53bcea052e075c53f89df3d2a33e","Linux cb1831a83e54cd3269a2420fce81c4fd8ae6f667","Linux 1c37ff78298a6b6063649123356a312e1cce12ca","Linux f17c786b28a3060a566a170c2cf3bd7441fc30a3","Linux >= 4.4.103 < 4.5","Linux >= 4.9.66 < 4.10","Linux >= 4.14.3 < 4.15","Linux 4.15"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"partial","timestamp":"2026-11-06T15:44:31.654477Z"},"published":"2026-05-27","updated":"2026-11-06","sourceUpdated":"2026-11-06T15:53:12.903Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-45919","references":[{"url":"https://git.kernel.org/stable/c/d57d0746276a88ea43a2cc62b849fd8a95e32e41"},{"url":"https://git.kernel.org/stable/c/3b3c672a66db3de3b40f8a7057864bc1f874ede3"},{"url":"https://git.kernel.org/stable/c/16ca9f3117e9a294646c897daf08a5ab546c711b"},{"url":"https://git.kernel.org/stable/c/8ad5577b2d4acfd83f03d97a0aece2d18aac5f07"},{"url":"https://git.kernel.org/stable/c/a6a73403733e86748421f2eeaf028c85683ef896"},{"url":"https://git.kernel.org/stable/c/52aeb1e07ec223caf212f036817976c98d2aa250"},{"url":"https://git.kernel.org/stable/c/9f25edc5a20cb52a5abbf25f0724bb4732b81801"},{"url":"https://git.kernel.org/stable/c/94894c9c477e53bcea052e075c53f89df3d2a33e"}],"tags":["cve.org"],"epss":0.0013,"epssPercentile":0.02691,"ingestedAt":"2026-11-06T16:57:43.386Z","slug":"CVE-2026-45919","body":"## Overview\n\nIn 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.\n\n## Affected\n\n- `Linux >= 4bdced5c9a2922521e325896a7bbbf0132c94e56 < d57d0746276a88ea43a2cc62b849fd8a95e32e41`\n- `Linux >= 4bdced5c9a2922521e325896a7bbbf0132c94e56 < 3b3c672a66db3de3b40f8a7057864bc1f874ede3`\n- `Linux >= 4bdced5c9a2922521e325896a7bbbf0132c94e56 < 16ca9f3117e9a294646c897daf08a5ab546c711b`\n- `Linux >= 4bdced5c9a2922521e325896a7bbbf0132c94e56 < 8ad5577b2d4acfd83f03d97a0aece2d18aac5f07`\n- `Linux >= 4bdced5c9a2922521e325896a7bbbf0132c94e56 < a6a73403733e86748421f2eeaf028c85683ef896`\n- `Linux >= 4bdced5c9a2922521e325896a7bbbf0132c94e56 < 52aeb1e07ec223caf212f036817976c98d2aa250`\n- `Linux >= 4bdced5c9a2922521e325896a7bbbf0132c94e56 < 9f25edc5a20cb52a5abbf25f0724bb4732b81801`\n- `Linux >= 4bdced5c9a2922521e325896a7bbbf0132c94e56 < 94894c9c477e53bcea052e075c53f89df3d2a33e`\n- `Linux cb1831a83e54cd3269a2420fce81c4fd8ae6f667`\n- `Linux 1c37ff78298a6b6063649123356a312e1cce12ca`\n- `Linux f17c786b28a3060a566a170c2cf3bd7441fc30a3`\n- `Linux >= 4.4.103 < 4.5`\n- `Linux >= 4.9.66 < 4.10`\n- `Linux >= 4.14.3 < 4.15`\n- `Linux 4.15`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}