What’s Vulnerable › Vulnerabilities

CVE-2024-46750: PCI: Add missing bridge lock to pci_bus_lock()

• Severity: medium (CVSS 5.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2024-09-18 · updated 2026-10-15
• Weakness: CWE-667

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_bridge(dev); if (bridge) pci_dev_lock(bridge); to pci_reset_function() for the "bus" and "cxl_bus" reset cases, add pci_dev_lock() for @bus->self to pci_bus_lock(). [bhelgaas: squash in recursive locking deadlock fix from Keith Busch: https://lore.kernel.org/r/20240711193650.701834-1-kbusch@meta.com]

Affected products

• Linux kernel: before 4.19.322; from 4.20 before 5.4.284; from 5.5 before 5.10.226; from 5.11 before 5.15.167; from 5.16 before 6.1.110; from 6.2 before 6.6.51 — fixed in 4.19.322, 5.10.226, 5.15.167, 5.4.284, 6.1.110, 6.10.10

How to fix

Upgrade to a fixed version: Linux kernel 4.19.322, 5.10.226, 5.15.167, 5.4.284. Check the vendor advisory for mitigations.

References

• https://git.kernel.org/stable/c/04e85a3285b0e5c5af6fd2c0fd6e95ffecc01945
• https://git.kernel.org/stable/c/0790b89c7e911003b8c50ae50e3ac7645de1fae9
• https://git.kernel.org/stable/c/7253b4fed46471cc247c6cacefac890a8472c083
• https://git.kernel.org/stable/c/78c6e39fef5c428960aff742149bba302dd46f5a
• https://git.kernel.org/stable/c/81c68e218ab883dfa368460a59b674084c0240da
• https://git.kernel.org/stable/c/a4e772898f8bf2e7e1cf661a12c60a5612c4afab
• https://git.kernel.org/stable/c/df77a678c33871a6e4ac5b54a71662f1d702335b
• https://git.kernel.org/stable/c/e2355d513b89a2cb511b4ded0deb426cdb01acd0
• https://lists.debian.org/debian-lts-announce/2024/10/msg00003.html
• https://lists.debian.org/debian-lts-announce/2025/01/msg00001.html
• https://cert-portal.siemens.com/productcert/html/ssa-265688.html
• https://cert-portal.siemens.com/productcert/html/ssa-355557.html

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