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CONFIG_NUMA=n. NODE_DATA(nid)->node_zonelists[ZONELIST_FALLBACK] - before offline operation [0] - ZONE_MOVABLE [1] - ZONE_NORMAL [2] - NULL For a GFP_KERNEL allocation, alloc_pages_slowpath() will save the offset of ZONE_NORMAL in ac->preferred_zoneref. If a concurrent memory_offline operation removes the last page from ZONE_MOVABLE, build_all_zonelists() & build_zonerefs_node() will update node_zonelists as shown below. Only populated zones are added. NODE_DATA(nid)->node_zonelists[ZONELIST_FALLBACK] - after offline operation [0] - ZONE_NORMAL [1] - NULL [2] - NULL The thread in alloc_pages_slowpath() will call get_page_from_freelist() repeatedly to allocate from the zones in zonelist beginning from preferred_zoneref. Since this is now NULL, it will never succeed, and OOM killer will kill all killable processes. I noticed a comment on a recent change bb7645c33869 ("mm, page_alloc: fix build_zonerefs_node()") which appeared to be relevant, but later replies indicated concerns with performance implications. https://lore.kernel.org/linux-mm/Yk7NqTlw7lmFzpKb@dhcp22.suse.cz/