CVE-2025-68333
Unknown Unknown - Not Provided
Deadlock Vulnerability in Linux Kernel sched_ext Deferred IRQ Workfn

Publication date: 2025-12-22

Last updated on: 2026-02-26

Assigner: kernel.org

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.
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Meta Information
Published
2025-12-22
Last Modified
2026-02-26
Generated
2026-06-16
AI Q&A
2025-12-23
EPSS Evaluated
2026-06-15
NVD
CVE-2025-68333
Affected Vendors & Products
Showing 8 associated CPEs
Vendor Product Version / Range
linux linux_kernel 6.18
linux linux_kernel 6.18
linux linux_kernel 6.18
linux linux_kernel 6.18
linux linux_kernel 6.18
linux linux_kernel 6.18
linux linux_kernel From 6.12 (inc) to 6.12.68 (exc)
linux linux_kernel From 6.13 (inc) to 6.17.12 (exc)
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-667 The product does not properly acquire or release a lock on a resource, leading to unexpected resource state changes and behaviors.
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Executive Summary

This vulnerability is a possible deadlock in the Linux kernel's deferred_irq_workfn() function when running PREEMPT_RT=y kernels. The issue arises because deferred_irq_workfn() is executed in the per-CPU irq_work task context rather than a hard interrupt context. If the runqueue (rq) returned by container_of() corresponds to the current CPU's rq, a scenario can occur where the rq lock is acquired, an interrupt happens, and then the same rq lock is attempted to be acquired again, causing a deadlock. The fix replaces init_irq_work() with IRQ_WORK_INIT_HARD() to ensure deferred_irq_workfn() always runs in hard-irq context, preventing this deadlock.

Impact Analysis

This vulnerability can cause a deadlock in the Linux kernel on systems using PREEMPT_RT=y kernels, potentially leading to system hangs or degraded performance due to the kernel being stuck waiting for a lock that cannot be acquired. This can affect system stability and responsiveness.

Mitigation Strategies

To mitigate this vulnerability, update your Linux kernel to a version that includes the fix for the deferred_irq_workfn() deadlock issue. The fix involves using IRQ_WORK_INIT_HARD() to initialize rq->scx.deferred_irq_work, ensuring the deferred_irq_workfn() is always invoked in hard-irq context. Applying the latest kernel patches or upgrading to the fixed kernel version is recommended.

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