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CVE PROGRAM SOURCE RECORD7.8 High

CVE-2026-74594

sched/psi: Shut down rtpoll_timer in psi_cgroup_free()

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Status
Published
Published
Updated
Assigning organization
Linux

Description

In the Linux kernel, the following vulnerability has been resolved: sched/psi: Shut down rtpoll_timer in psi_cgroup_free() psi_schedule_rtpoll_work() is called locklessly from the scheduler hotpath and can race psi_trigger_destroy() taking down the last rtpoll trigger under rtpoll_trigger_lock: psi_schedule_rtpoll_work() psi_trigger_destroy() rcu_read_lock(); task = rcu_dereference(rtpoll_task); rcu_assign_pointer(rtpoll_task, NULL); timer_delete(&rtpoll_timer); mod_timer(&rtpoll_timer, ...); rcu_read_unlock(); synchronize_rcu(); kthread_stop(task_to_destroy); The group can then be freed with the re-armed timer still pending, and poll_timer_fn() runs on freed memory. 461daba06bdc ("psi: eliminate kthread_worker from psi trigger scheduling mechanism") deleted the timer synchronously after the synchronize_rcu(), which prevented this but raced trigger creation instead: the deletion could cancel the timer that a new trigger set armed during the grace period and, as creation also reinitialized the timer at the time, corrupt it. 8f91efd870ea ("psi: Fix race between psi_trigger_create/destroy") moved the initialization into group_init() and the deletion into the locked section, trading the creation races for the window above. Neither placement in the destruction path works. A pending timer firing while the group is alive is harmless though. poll_timer_fn() just wakes the rtpoll waitqueue and doesn't re-arm itself. Bind the timer to the group's lifetime instead and shut it down in psi_cgroup_free(). Nothing can arm it by then. timer_shutdown_sync() because the timer is never armed again.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

Linux Linux

Default version status: unaffected

  • 6bfcb6178925b1fd28c102e53d403091b8f49396 to < 4addb102154b7cf6e2310ccbe20c3c08619e520daffected
  • 8f91efd870ea5d8bc10b0fcc9740db51cd4c0c83 to < 894a9300d7fb2e2951da92e565ae6de7ddfb0a69affected
  • 8f91efd870ea5d8bc10b0fcc9740db51cd4c0c83 to < 1e5ca82eee59caca6988f9d6e859786aab8a5fa0affected
  • 8f91efd870ea5d8bc10b0fcc9740db51cd4c0c83 to < 310b5a537a78c358a4cd244bd767c1a517a05459affected
  • 8f91efd870ea5d8bc10b0fcc9740db51cd4c0c83 to < 806fcff98c1d7cb3c1dc0015e55ebdbe819e6b08affected
  • 8f91efd870ea5d8bc10b0fcc9740db51cd4c0c83 to < 8037c5b2b2a447df52542f4d8535895d837bdcbdaffected
  • 8f91efd870ea5d8bc10b0fcc9740db51cd4c0c83 to < 611e7821c4f83a671455658797336faecc3a5196affected
  • 8f91efd870ea5d8bc10b0fcc9740db51cd4c0c83 to < 5457025fa8ca3c0d2732109513de839e3e797190affected
  • e1e5e263bbe0e6e9c3db36aa48a3c8acf546fa49affected
  • 979965c33f734a1666af67900408f997ac669c23affected
  • 5.10.50 to < 5.10.266affected
  • 5.12.17 to < 5.13affected
  • 5.13.2 to < 5.14affected

Linux Linux

Default version status: affected

  • 5.14affected
  • 0 to < 5.14unaffected
  • 5.10.266 to ≤ 5.10.*unaffected
  • 5.15.217 to ≤ 5.15.*unaffected
  • 6.1.183 to ≤ 6.1.*unaffected
  • 6.6.152 to ≤ 6.6.*unaffected
  • 6.12.104 to ≤ 6.12.*unaffected
  • 6.18.45 to ≤ 6.18.*unaffected
  • 7.1.9 to ≤ 7.1.*unaffected
  • 7.2 to ≤ *unaffected

References