{"id":"AZL-74495","summary":"CVE-2025-68780 affecting package kernel for versions less than 6.6.121.1-1","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nsched/deadline: only set free_cpus for online runqueues\n\nCommit 16b269436b72 (\"sched/deadline: Modify cpudl::free_cpus\nto reflect rd-\u003eonline\") introduced the cpudl_set/clear_freecpu\nfunctions to allow the cpu_dl::free_cpus mask to be manipulated\nby the deadline scheduler class rq_on/offline callbacks so the\nmask would also reflect this state.\n\nCommit 9659e1eeee28 (\"sched/deadline: Remove cpu_active_mask\nfrom cpudl_find()\") removed the check of the cpu_active_mask to\nsave some processing on the premise that the cpudl::free_cpus\nmask already reflected the runqueue online state.\n\nUnfortunately, there are cases where it is possible for the\ncpudl_clear function to set the free_cpus bit for a CPU when the\ndeadline runqueue is offline. When this occurs while a CPU is\nconnected to the default root domain the flag may retain the bad\nstate after the CPU has been unplugged. Later, a different CPU\nthat is transitioning through the default root domain may push a\ndeadline task to the powered down CPU when cpudl_find sees its\nfree_cpus bit is set. If this happens the task will not have the\nopportunity to run.\n\nOne example is outlined here:\nhttps://lore.kernel.org/lkml/20250110233010.2339521-1-opendmb@gmail.com\n\nAnother occurs when the last deadline task is migrated from a\nCPU that has an offlined runqueue. The dequeue_task member of\nthe deadline scheduler class will eventually call cpudl_clear\nand set the free_cpus bit for the CPU.\n\nThis commit modifies the cpudl_clear function to be aware of the\nonline state of the deadline runqueue so that the free_cpus mask\ncan be updated appropriately.\n\nIt is no longer necessary to manage the mask outside of the\ncpudl_set/clear functions so the cpudl_set/clear_freecpu\nfunctions are removed. In addition, since the free_cpus mask is\nnow only updated under the cpudl lock the code was changed to\nuse the non-atomic __cpumask functions.","modified":"2026-04-01T05:22:43.794283Z","published":"2026-01-13T16:15:57Z","upstream":["CVE-2025-68780"],"references":[{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2025-68780"}],"affected":[{"package":{"name":"kernel","ecosystem":"Azure Linux:3","purl":"pkg:rpm/azure-linux/kernel"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.6.121.1-1"}]}],"database_specific":{"source":"https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-74495.json"}}],"schema_version":"1.7.5"}