CVE-2026-74468
In the Linux kernel, the following vulnerability has been resolved:
gpio: pch: use raw_spinlock_t for the register lock
pch_irq_type() is registered as the irq_chip .irq_set_type callback and
takes chip->spinlock with spin_lock_irqsave(). This callback is reached
from __setup_irq() -> __irq_set_trigger() -> chip->irq_set_type() while
the caller holds desc->lock, a raw_spinlock_t, with hardirqs disabled.
That context is not sleepable, but on PREEMPT_RT a regular spinlock_t is
an rtmutex-backed sleeping lock, so acquiring it there is invalid.
This was confirmed on a PREEMPT_RT kernel with lockdep
(PROVE_RAW_LOCK_NESTING and DEBUG_ATOMIC_SLEEP). A grounded PoC mirrored
pch_irq_type()'s locking and drove it through the real genirq carrier
irq_set_irq_type() -> __irq_set_trigger() -> chip->irq_set_type(), i.e.
the same __irq_set_trigger() edge that __setup_irq() takes for a
requested IRQ. With the original spin_lock_irqsave() edge lockdep
reported an invalid wait context, immediately followed by:
BUG: sleeping function called from invalid context at kernel/locking/spinlock_rt.c:48
in_atomic(): 1, irqs_disabled(): 1, non_block: 0, pid: 95, name: insmod
hardirqs last disabled at (3784): _raw_spin_lock_irqsave+0x4f/0x60
rt_spin_lock+0x3a/0x1c0
repro_irq_set_type+0x64/0xa0 [pch_repro]
__irq_set_trigger+0x69/0x140
irq_set_irq_type+0x78/0xd0
Switching the mirrored lock to raw_spinlock_t made both splats go away.
Convert the register lock to raw_spinlock_t. The same lock also
serializes the GPIO direction/value callbacks and the suspend/resume
register save/restore, but all of those critical sections only perform
MMIO register accesses (ioread32()/iowrite32()) and
irq_set_handler_locked(); none of them 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.
This is the same class of issue and fix as recently addressed for other
GPIO c
CSIRTS triage
- What
- Multiple vulnerabilities in the Linux kernel that may result in privilege escalation, denial of service, or information disclosure.
- Who is affected
- Debian systems running vulnerable Linux kernel versions.
- Urgency
- Multiple kernel vulnerabilities enabling privilege escalation and information leaks require urgent patching to protect system and data security.
- Action
- Apply the Debian security update DSA-6466-1 to the Linux kernel immediately.
AI-assisted analysis generated from the source advisory — verify against the original.
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Exploitation outlook
- Low exploitation risk0.18% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 8% of all EPSS-scored CVEs.
Advisory coverage (2)
- unknownDSA-6466-1 linux - security updatedebian · 2026-08-25
- unknownCVE-2026-74468: In the Linux kernel, the following vulnerability has been resolved: gpio: pch: use raw_spinloc…nvd · 2026-08-15
External references
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