Affected: Alpaquita:23: linux-lts, Alpaquita:25: linux-lts, Alpaquita:stream: linux-lts

In the Linux kernel, the following vulnerability has been resolved:

gpio: ml-ioh: use raw_spinlock_t for the register lock

ioh_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. ioh_irq_enable() and ioh_irq_disable() take the same lock from the .irq_enable/.irq_disable callbacks, which are likewise invoked with desc->lock held.

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, and those critical sections only perform short sequences of MMIO register accesses (ioread32()/iowrite32()); the .irq_set_type callback additionally emits a dev_warn() on an unsupported type. None of these are sleepable operations, so keeping this register lock non-sleeping is appropriate for the irqchip callbacks and does not change the GPIO-side locking contract.

This is the same fix as commit a02b8950d619 ("gpio: pch: use raw_spinlock_t for the register lock"); this driver shares the same structure as gpio-pch.

In the Linux kernel, the following vulnerability has been resolved:

gpio: ml-ioh: use raw_spinlock_t for the register lock

ioh_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. ioh_irq_enable() and ioh_irq_disable() take the same lock from the .irq_enable/.irq_disable callbacks, which are likewise invoked with desc->lock held.

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, and those critical sections only perform short sequences of MMIO register accesses (ioread32()/iowrite32()); the .irq_set_type callback additionally emits a dev_warn() on an unsupported type. None of these are sleepable operations, so keeping this register lock non-sleeping is appropriate for the irqchip callbacks and does not change the GPIO-side locking contract.

This is the same fix as commit a02b8950d619 ("gpio: pch: use raw_spinlock_t for the register lock"); this driver shares the same structure as gpio-pch.

Affected: Ubuntu:Pro:14.04:LTS: linux, Ubuntu:Pro:14.04:LTS: linux-aws, Ubuntu:Pro:14.04:LTS: linux-azure, Ubuntu:Pro:14.04:LTS: linux-lts-xenial, Ubuntu:Pro:16.04:LTS: linux, Ubuntu:Pro:16.04:LTS: linux-aws, Ubuntu:Pro:16.04:LTS: linux-aws-hwe, Ubuntu:Pro:16.04:LTS: linux-azure, Ubuntu:Pro:16.04:LTS: linux-gcp, Ubuntu:Pro:16.04:LTS: linux-hwe and 247 more

In the Linux kernel, the following vulnerability has been resolved: gpio: ml-ioh: use raw_spinlock_t for the register lock ioh_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. ioh_irq_enable() and ioh_irq_disable() take the same lock from the .irq_enable/.irq_disable callbacks, which are likewise invoked with desc->lock held. 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, and those critical sections only perform short sequences of MMIO register accesses (ioread32()/iowrite32()); the .irq_set_type callback additionally emits a dev_warn() on an unsupported type. None of these are sleepable operations, so keeping this register lock non-sleeping is appropriate for the irqchip callbacks and does not change the GPIO-side locking contract. This is the same fix as commit a02b8950d619 ("gpio: pch: use raw_spinlock_t for the register lock"); this driver shares the same structure as gpio-pch.

Ein Angreifer kann mehrere Schwachstellen im Linux Kernel ausnutzen, um einen nicht näher spezifizierten Angriff durchzuführen, darunter möglicherweise die Ausführung von beliebigem Code, die Ausweitung von Berechtigungen, die Offenlegung von Informationen, die Manipulation von Daten oder Denial-of-Service-Zustände.