CVE-2026-43326 (GCVE-0-2026-43326)

Vulnerability from cvelistv5 – Published: 2026-05-08 13:31 – Updated: 2026-05-11 22:22
VLAI
Title
sched_ext: Fix SCX_KICK_WAIT deadlock by deferring wait to balance callback
Summary
In the Linux kernel, the following vulnerability has been resolved: sched_ext: Fix SCX_KICK_WAIT deadlock by deferring wait to balance callback SCX_KICK_WAIT busy-waits in kick_cpus_irq_workfn() using smp_cond_load_acquire() until the target CPU's kick_sync advances. Because the irq_work runs in hardirq context, the waiting CPU cannot reschedule and its own kick_sync never advances. If multiple CPUs form a wait cycle, all CPUs deadlock. Replace the busy-wait in kick_cpus_irq_workfn() with resched_curr() to force the CPU through do_pick_task_scx(), which queues a balance callback to perform the wait. The balance callback drops the rq lock and enables IRQs following the sched_core_balance() pattern, so the CPU can process IPIs while waiting. The local CPU's kick_sync is advanced on entry to do_pick_task_scx() and continuously during the wait, ensuring any CPU that starts waiting for us sees the advancement and cannot form cyclic dependencies.
Severity
5.5 (Medium)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 90e55164dad42c6546b698c031697b224a320834 , < c3a7903f65cf4c7fb0477eb0f8b94f326a47fe54 (git)
Affected: 90e55164dad42c6546b698c031697b224a320834 , < 415cb193bb9736f0e830286c72a6fa8eb2a9cc5c (git)
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Linux Linux Affected: 6.12
Unaffected: 0 , < 6.12 (semver)
Unaffected: 6.19.12 , ≤ 6.19.* (semver)
Unaffected: 7.0 , ≤ * (original_commit_for_fix)
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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
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