In the Linux kernel, the following vulnerability has been resolved:
iommu/amd: Do not reallocate GA log buffers on resume
Commit c5e1a1eb9279 (“iommu/amd: Simplify and Consolidate Virtual APIC
(AVIC) Enablement”) moved the GA log allocation from iommu_init_pci()
to enable_iommus_vapic(), which is called on every resume.
iommu_init_ga_log() assigns iommu->ga_log and iommu->ga_log_tail
unconditionally. Each resume therefore replaces the boot-time pointers
and leaks both old allocations. The function also uses GFP_KERNEL from a
syscore resume callback, where interrupts are disabled and the non-boot
CPUs are offline.
Return early if both buffers are already allocated. Clear the pointers
in free_ga_log() so a partial allocation failure cannot leave ga_log
dangling.
