{"id":"CVE-2026-74594","aliases":[],"url":"https://o3.security/vulnerability/CVE-2026-74594","summary":"sched/psi: Shut down rtpoll_timer in psi_cgroup_free()","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.","published":"2026-08-22T15:31:44.894Z","modified":"2026-08-25T03:51:31.649532719Z","cvss":null,"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[{"ecosystem":"Linux","name":"Kernel","fixedVersion":"5.10.266"}],"fix":null,"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/1e5ca82eee59caca6988f9d6e859786aab8a5fa0"},{"type":"WEB","url":"https://git.kernel.org/stable/c/310b5a537a78c358a4cd244bd767c1a517a05459"},{"type":"WEB","url":"https://git.kernel.org/stable/c/4addb102154b7cf6e2310ccbe20c3c08619e520d"},{"type":"WEB","url":"https://git.kernel.org/stable/c/5457025fa8ca3c0d2732109513de839e3e797190"},{"type":"WEB","url":"https://git.kernel.org/stable/c/611e7821c4f83a671455658797336faecc3a5196"},{"type":"WEB","url":"https://git.kernel.org/stable/c/8037c5b2b2a447df52542f4d8535895d837bdcbd"},{"type":"WEB","url":"https://git.kernel.org/stable/c/806fcff98c1d7cb3c1dc0015e55ebdbe819e6b08"},{"type":"WEB","url":"https://git.kernel.org/stable/c/894a9300d7fb2e2951da92e565ae6de7ddfb0a69"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/74xxx/CVE-2026-74594.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-74594"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-25T03:51:31.649532719Z"}}