CVE-2024-46750

/// Technical description

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

PCI: Add missing bridge lock to pci_bus_lock()

One of the true positives that the cfg_access_lock lockdep effort

identified is this sequence:

WARNING: CPU: 14 PID: 1 at drivers/pci/pci.c:4886 pci_bridge_secondary_bus_reset+0x5d/0x70

RIP: 0010:pci_bridge_secondary_bus_reset+0x5d/0x70

Call Trace:

<TASK>

? __warn+0x8c/0x190

? pci_bridge_secondary_bus_reset+0x5d/0x70

? report_bug+0x1f8/0x200

? handle_bug+0x3c/0x70

? exc_invalid_op+0x18/0x70

? asm_exc_invalid_op+0x1a/0x20

? pci_bridge_secondary_bus_reset+0x5d/0x70

pci_reset_bus+0x1d8/0x270

vmd_probe+0x778/0xa10

pci_device_probe+0x95/0x120

Where pci_reset_bus() users are triggering unlocked secondary bus resets.

Ironically pci_bus_reset(), several calls down from pci_reset_bus(), uses

pci_bus_lock() before issuing the reset which locks everything *but* the

bridge itself.

For the same motivation as adding:

bridge = pci_upstream_b

/// 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