CVE-2024-56568: Linux Kernel

Medium severity, CVSS 4.7. EPSS: 0.2% chance of exploitation in the next 30 days.

In the Linux kernel, the following vulnerability has been resolved: iommu/arm-smmu: Defer probe of clients after smmu device bound Null pointer dereference occurs due to a race between smmu driver probe and client driver probe, when of_dma_configure() for client is called after the iommu_device_register() for smmu driver probe has executed but before the driver_bound() for smmu driver has been called. Following is how the race occurs: T1:Smmu device probe T2: Client device probe really_probe() arm_smmu_device_probe() iommu_device_register() really_probe() platform_dma_configure() of_dma_configure() of_dma_configure_id() of_iommu_configure() iommu_probe_device() iommu_init_device() arm_smmu_probe_device() arm_smmu_get_by_fwnode() driver_find_device_by_fwnode() driver_find_device() next_device() klist_next() /* null ptr assigned to smmu */ /* null ptr dereference while smmu->streamid_mask */ driver_bound() klist_add_tail() When this null smmu pointer is dereferenced later in arm_smmu_probe_device, the device crashes. Fix this by deferring the probe of the client device until the smmu device has bound to the arm smmu driver. [will: Add comment]

Affected products

• Linux Linux Kernel: from 4.9, before 5.10.231 (fixed in 5.10.231); from 5.11, before 5.15.174 (fixed in 5.15.174); from 5.16, before 6.1.120 (fixed in 6.1.120); from 6.2, before 6.6.66 (fixed in 6.6.66); from 6.7, before 6.12.4 (fixed in 6.12.4)

Published 2024-12-27. Last modified 2026-06-17.