"value":"In the Linux kernel, the following vulnerability has been resolved:\n\nmm: fix NULL pointer dereference in alloc_pages_bulk_noprof\n\nWe triggered a NULL pointer dereference for ac.preferred_zoneref->zone in\nalloc_pages_bulk_noprof() when the task is migrated between cpusets.\n\nWhen cpuset is enabled, in prepare_alloc_pages(), ac->nodemask may be\n¤t->mems_allowed. when first_zones_zonelist() is called to find\npreferred_zoneref, the ac->nodemask may be modified concurrently if the\ntask is migrated between different cpusets. Assuming we have 2 NUMA Node,\nwhen traversing Node1 in ac->zonelist, the nodemask is 2, and when\ntraversing Node2 in ac->zonelist, the nodemask is 1. As a result, the\nac->preferred_zoneref points to NULL zone.\n\nIn alloc_pages_bulk_noprof(), for_each_zone_zonelist_nodemask() finds a\nallowable zone and calls zonelist_node_idx(ac.preferred_zoneref), leading\nto NULL pointer dereference.\n\n__alloc_pages_noprof() fixes this issue by checking NULL pointer in commit\nea57485af8f4 (\"mm, page_alloc: fix check for NULL preferred_zone\") and\ncommit df76cee6bbeb (\"mm, page_alloc: remove redundant checks from alloc\nfastpath\").\n\nTo fix it, check NULL pointer for preferred_zoneref->zone."