Medium [CVE-2026-64428] use raw_spinlock_t in the irq startup path
This medium-severity Red Hat Linux advisory covers CVE-2026-64428 affecting Red Hat Enterprise Linux 6, Red Hat package: kernel.
Aggregated and source-linked by VulniPulse. Data sources, validation and limitations.
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Summary
In the Linux kernel, the following vulnerability has been resolved: gpio: sch: use raw_spinlock_t in the irq startup path sch_irq_unmask() enables the GPIO IRQ and then updates the controller state through sch_irq_mask_unmask(), which takes sch->lock with spin_lock_irqsave(). The callback can be reached from irq_startup() while setting up a requested IRQ.
That path is not sleepable, but on PREEMPT_RT a regular spinlock_t becomes a sleeping lock. This issue was found by our static analysis tool and then manually reviewed against the current tree.
The grounded PoC kept the request_threaded_irq() -> __setup_irq() -> irq_startup() -> sch_irq_unmask() -> sch_irq_mask_unmask() carrier and used the original spin_lock_irqsave(&sch->lock) edge.
Lockdep reported: BUG: sleeping function called from invalid context hardirqs last disabled at... __setup_irq.constprop.0... [vuln_msv] sch_rt_spin_lock_irqsave+0x1c/0x30 [vuln_msv] sch_irq_mask_unmask.constprop.0+0x31/0x70 [vuln_msv] __setup_irq.constprop.0+0xd/0x30 [vuln_msv] Convert the SCH controller lock to raw_spinlock_t.
The same lock is also used by the GPIO direction and value callbacks, but those critical sections only update MMIO-backed GPIO registers and do not contain sleepable operations. Keeping this register lock non-sleeping is therefore appropriate for the irqchip callbacks and does not change the GPIO-side locking contract.
Affected versions
No affected-version range was extracted from the source record. The vendor advisory is authoritative. Check it before change work.
Official advisory · medium-confidence parse· fetched 1 month ago·verify at source
Fixed versions
No fixed release is recorded yet. That does not prove no patch exists. Confirm against the vendor advisory.
Official advisory · medium-confidence parse· fetched 1 month ago·verify at source
Mitigation
The source record does not include mitigation steps. That does not mean no fix exists. Read the vendor advisory below for the authoritative guidance.
Official advisory · medium-confidence parse· fetched 1 month ago·verify at source
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