CVE-2026-64430

/// Technical description

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

NTB: epf: Avoid calling pci_irq_vector() from hardirq context

ntb_epf_vec_isr() calls pci_irq_vector() in hardirq context to derive

the vector number. pci_irq_vector() calls msi_get_virq() that takes a

mutex and can therefore trigger "scheduling while atomic" splats:

BUG: scheduling while atomic: kworker/u33:0/55/0x00010001

...

Call trace:

...

schedule+0x38/0x110

schedule_preempt_disabled+0x28/0x50

__mutex_lock.constprop.0+0x848/0x908

__mutex_lock_slowpath+0x18/0x30

mutex_lock+0x4c/0x60

msi_domain_get_virq+0xe8/0x138

pci_irq_vector+0x2c/0x60

ntb_epf_vec_isr+0x28/0x120 [ntb_hw_epf]

__handle_irq_event_percpu+0x70/0x3a8

handle_irq_event+0x48/0x100

handle_edge_irq+0x100/0x1c8

...

Cache the Linux IRQ number for vector 0 when vectors are allocated and

use it as a base in the ISR. Running the ISR in a threaded IRQ handler

would also avoid the problem, but that would be unnecess

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References