CVE-2026-43448 — nvme-pci: Fix race bug in nvme_poll_irqdisable()

Affected: Linux

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

nvme-pci: Fix race bug in nvme_poll_irqdisable()

In the following scenario, pdev can be disabled between (1) and (3) by (2). This sets pdev->msix_enabled = 0. Then, pci_irq_vector() will return MSI-X IRQ(>15) for (1) whereas return INTx IRQ(<=15) for (2). This causes IRQ warning because it tries to enable INTx IRQ that has never been disabled before.

To fix this, save IRQ number into a local variable and ensure disable_irq() and enable_irq() operate on the same IRQ number. Even if pci_free_irq_vectors() frees the IRQ concurrently, disable_irq() and enable_irq() on a stale IRQ number is still valid and safe, and the depth accounting reamins balanced.

task 1: nvme_poll_irqdisable() disable_irq(pci_irq_vector(pdev, nvmeq->cq_vector)) ...(1) enable_irq(pci_irq_vector(pdev, nvmeq->cq_vector)) ...(3)

task 2: nvme_reset_work() nvme_dev_disable() pdev->msix_enable = 0; ...(2)

crash log:

------------[ cut here ]------------ Unbalanced enable for IRQ 10 WARNING: kernel/irq/manage.c:753 at __enable_irq+0x102/0x190 kernel/irq/manage.c:753, CPU#1: kworker/1:0H/26 Modules linked in: CPU: 1 UID: 0 PID: 26 Comm: kworker/1:0H Not tainted 6.19.0-dirty #9 PREEMPT(voluntary) Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014 Workqueue: kblockd blk_mq_timeout_work RIP: 0010:__enable_irq+0x107/0x190 kernel/irq/manage.c:753 Code: ff df 48 89 fa 48…

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CVE-2026-43448 — nvme-pci: Fix race bug in nvme_poll_irqdisable()