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CVE-2025-68333: sched_ext: Fix possible deadlock in the deferred_irq_workfn()

• Severity: medium (CVSS 5.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.1% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2025-12-22 · updated 2026-10-19
• Weakness: CWE-667

Description

In the Linux kernel, the following vulnerability has been resolved: sched_ext: Fix possible deadlock in the deferred_irq_workfn() For PREEMPT_RT=y kernels, the deferred_irq_workfn() is executed in the per-cpu irq_work/* task context and not disable-irq, if the rq returned by container_of() is current CPU's rq, the following scenarios may occur: lock(&rq->__lock); <Interrupt> lock(&rq->__lock); This commit use IRQ_WORK_INIT_HARD() to replace init_irq_work() to initialize rq->scx.deferred_irq_work, make the deferred_irq_workfn() is always invoked in hard-irq context.

Affected products

• Linux kernel: from 6.12 before 6.12.68; from 6.13 before 6.17.12; 6.18-rc1, 6.18-rc2, 6.18-rc3, 6.18-rc4, 6.18-rc5, 6.18-rc6 — fixed in 6.12.68, 6.17.12

How to fix

Upgrade to a fixed version: Linux kernel 6.12.68, 6.17.12. Check the vendor advisory for mitigations.

References

• https://git.kernel.org/stable/c/541959b2fadb832a7d0ceb95041dc52bdcf6bff7
• https://git.kernel.org/stable/c/600b4379b9a7ba41340d652211fb29699da4c629
• https://git.kernel.org/stable/c/a257e974210320ede524f340ffe16bf4bf0dda1e

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