{"id":"AZL-97302","summary":"CVE-2026-74594 affecting package kernel 6.6.150.1-1","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nsched/psi: Shut down rtpoll_timer in psi_cgroup_free()\n\npsi_schedule_rtpoll_work() is called locklessly from the scheduler hotpath\nand can race psi_trigger_destroy() taking down the last rtpoll trigger under\nrtpoll_trigger_lock:\n\n  psi_schedule_rtpoll_work()        psi_trigger_destroy()\n\n  rcu_read_lock();\n  task = rcu_dereference(rtpoll_task);\n                                    rcu_assign_pointer(rtpoll_task, NULL);\n                                    timer_delete(&rtpoll_timer);\n  mod_timer(&rtpoll_timer, ...);\n  rcu_read_unlock();\n                                    synchronize_rcu();\n                                    kthread_stop(task_to_destroy);\n\nThe group can then be freed with the re-armed timer still pending, and\npoll_timer_fn() runs on freed memory.\n\n461daba06bdc (\"psi: eliminate kthread_worker from psi trigger scheduling\nmechanism\") deleted the timer synchronously after the synchronize_rcu(),\nwhich prevented this but raced trigger creation instead: the deletion could\ncancel the timer that a new trigger set armed during the grace period and,\nas creation also reinitialized the timer at the time, corrupt it.\n8f91efd870ea (\"psi: Fix race between psi_trigger_create/destroy\") moved the\ninitialization into group_init() and the deletion into the locked section,\ntrading the creation races for the window above.\n\nNeither placement in the destruction path works. A pending timer firing\nwhile the group is alive is harmless though. poll_timer_fn() just wakes the\nrtpoll waitqueue and doesn't re-arm itself. Bind the timer to the group's\nlifetime instead and shut it down in psi_cgroup_free(). Nothing can arm it\nby then. timer_shutdown_sync() because the timer is never armed again.","modified":"2026-08-29T05:27:27Z","published":"2026-08-22T16:16:31Z","upstream":["CVE-2026-74594"],"references":[{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-74594"}],"affected":[{"package":{"name":"kernel","ecosystem":"Azure Linux:3","purl":"pkg:rpm/azure-linux/kernel"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"6.6.150.1-1"}]}],"database_specific":{"source":"https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-97302.json"}}],"schema_version":"1.9.0"}