In the Linux kernel, the following vulnerability has been resolved: mm/sparsemem: fix race in accessing memory_section->usage The below race is observed on a PFN which falls into the device memory region with the system memory configuration where PFN's are such that [ZONE_NORMAL ZONE_DEVICE ZONE_NORMAL]. Since normal zone start and end pfn contains the device memory PFN's as well, the compaction triggered will try on the device memory PFN's too though they end up in NOP(because pfn_to_online_page() returns NULL for ZONE_DEVICE memory sections). When from other core, the section mappings are being removed for the ZONE_DEVICE region, that the PFN in question belongs to, on which compaction is currently being operated is resulting into the kernel crash with CONFIG_SPASEMEM_VMEMAP enabled. The crash logs can be seen at [1]. compact_zone() memunmap_pages ------------- --------------- __pageblock_pfn_to_page ...... (a)pfn_valid(): valid_section()//return true (b)…