Copyright © 2012 Red Hat, Inc. All rights reserved. Low 2026-07-25T00:00:00 kernel: NTB: epf: Avoid calling pci_irq_vector() from hardirq context 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H CWE-364

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 unnecessary here.

A flaw was found in the Linux kernel's Non-Transparent Bridge (NTB) Endpoint Function (EPF) component. During critical interrupt processing, the system attempts to acquire a lock, which is an operation not permitted in this context. This improper handling can lead to a system crash, resulting in a denial of service for the affected system.

Red Hat Enterprise Linux 10 Not affected kernel Red Hat Enterprise Linux 6 Not affected kernel Red Hat Enterprise Linux 7 Not affected kernel Red Hat Enterprise Linux 7 Not affected kernel-rt Red Hat Enterprise Linux 8 Not affected kernel Red Hat Enterprise Linux 8 Not affected kernel-rt Red Hat Enterprise Linux 9 Not affected kernel Red Hat Enterprise Linux 9 Not affected kernel-rt https://www.cve.org/CVERecord?id=CVE-2026-64430 https://nvd.nist.gov/vuln/detail/CVE-2026-64430 https://lore.kernel.org/linux-cve-announce/2026072536-CVE-2026-64430-3346@gregkh/T