cxl/region: Fill first free targets[] slot during auto-discovery

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-74274
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-15 06:22:26 UTC
Updated2026-08-15 06:22:26 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: cxl/region: Fill first free targets[] slot during auto-discovery Any invalid endpoint decoder pointer in the target array of an active region is not allowed by cxl driver. This means cxl driver always assumes the first p->nr_targets entries of the target array in an auto-assembly region are valid. However, there are scenarios that could leave NULL endpoint decoder pointer holes in the target array. 1. When cxl_cancel_auto_attach() removes an endpoint decoder from a target array, the target slot is set to NULL. If the removed endpoint decoder is not the last element in the target array, the target array will contain a NULL hole. 2. When a auto-assembly region removes an assigned endpoint decoder, if the removed endpoint decoder is not the last element in the target array, always remains a NULL hole in the target array. When a NULL pointer hole exists in a region's target array, it introduces two potential problems: 1. Access an endpoint decoder via a NULL pointer. it always trigger calltrace like that. Oops: general protection fault, probably for non-canonical address 0xdffffc0000000008: 0000 [#1] SMP KASAN PTI RIP: 0010:cxl_calc_interleave_pos+0x26/0x810 [cxl_core] Call Trace: <TASK> cxl_region_attach+0xc50/0x2140 [cxl_core] cxl_add_to_region+0x321/0x2330 [cxl_core] discover_region+0x92/0x150 [cxl_port] device_for_each_child+0xf3/0x170 cxl_port_probe+0x150/0x200 [cxl_port] cxl_bus_probe+0x4f/0xa0 [cxl_core] really_probe+0x1c8/0x960 __driver_probe_device+0x323/0x450 driver_probe_device+0x45/0x120 __device_attach_driver+0x15d/0x280 bus_for_each_drv+0x10f/0x190 2. Not having enough valid endpoint decoders attached to an auto-assembly region. if an auto-assembly region is created with lock flag or assigned endpoint decoder with lock flag, which means assigned endpoint decoder will not be reset during detaching, they could re-attach to the auto-assembly region again. But cxl region driver relies on p->nr_targets to verify whether the required number of endpoint decoders has been attached, and NULL endpoint decoder pointers are still counted in that case. To fix above issues, adjust cxl_region_attach_auto() logic to find the first free target slot for endpoint decoder attachment, this ensures NULL holes in the target array are filled, rather than adding new endpoint decoders at the tail of the target array.

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected 2230c4bdc4120417799c74326ade3123da226d54 6fde3fcdfec438ba0df26e25a8ac7c3707211799 git Not specified
CNA Linux Linux affected 2230c4bdc4120417799c74326ade3123da226d54 aa8a76711c15041ec1e42c3a74c15c2df0bd31f6 git Not specified
CNA Linux Linux affected 6.19 Not specified
CNA Linux Linux unaffected 6.19 semver Not specified
CNA Linux Linux unaffected 7.1.5 7.1.* semver Not specified
CNA Linux Linux unaffected 7.2-rc1 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/aa8a76711c15041ec1e42c3a74c15c2df0bd31f6 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/6fde3fcdfec438ba0df26e25a8ac7c3707211799 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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