CVE-2026-92521ACPI: PCI: Clear driver_data on all paths that free the acpi_pci_root

Official description

In the Linux kernel, the following vulnerability has been resolved: ACPI: PCI: Clear driver_data on all paths that free the acpi_pci_root acpi_pci_root_add() assigns the freshly allocated root to device->driver_data before dmar_device_add() and pci_acpi_scan_root(). Both failure paths reach the end: label where root is kfree()'d, but only the pci_acpi_scan_root() path clears driver_data first. When dmar_device_add() fails during a hot-add, root is freed while device->driver_data still points at it. The ACPI core does not clear driver_data on attach failure, so a later acpi_pci_find_root() call may dereference this dangling pointer. acpi_pci_root_remove() has the same problem: it frees root without clearing device->driver_data, leaving a dangling pointer behind after the root bridge is removed. Move the NULL assignment to the shared end: label so every error path in acpi_pci_root_add() clears driver_data before freeing root, and clear it in acpi_pci_root_remove() as well, so the object is never left reachable through driver_data after being freed.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/321bb0eb1486a0d575f02e24e3f4170e408c2f51
• https://git.kernel.org/stable/c/3c1e8a14f9d06c1ed6f3e4bd2d283a62079109e2
• https://git.kernel.org/stable/c/a285fa3780c768dcc51c76768707d099a2cc611d
• https://git.kernel.org/stable/c/6aaf6dbf54fdfae096f3f90a79e9614e46579280
• https://git.kernel.org/stable/c/70cf773cca30a10b4964c24520a71279c974b899
• https://git.kernel.org/stable/c/3eee4c21931dc048ce63b86809f04e4e6f0dcad5
• https://git.kernel.org/stable/c/6e11ac626f9f9fc3a2ed27dfa44ccbe5fb762217
• https://git.kernel.org/stable/c/8a742141f7ab84975aa758b775567ef4740ef0cf