From 2ebce860bdd7ae5e13002811bc9bbbf33fcfc221 Mon Sep 17 00:00:00 2001 From: Gregory Price Date: Wed, 1 Jul 2026 18:16:13 -0400 Subject: mm/mm_init: handle alloc_percpu failure in free_area_init_core_hotplug We miss a failed allocation check for pgdat->per_cpu_nodestats, which results in a NULL deref when we offset into the per-cpu area. Propagate -ENOMEM up the stack and leave per_cpu_nodestats pointing at boot_nodestats so a later online can retry the allocation. hotadd_init_pgdat() returns NULL on failure, which __try_online_node() already maps to -ENOMEM. On failure nothing needs to be unwound: - the node is never marked online - per_cpu_nodestats is left pointing at boot_nodestats - __add_memory_resource() cleans up pending memblock resources - later online attempts retry the per_cpu_nodestats allocation Reported-by: Sashiko Link: https://sashiko.dev/#/patchset/20260627202243.758289-1-gourry%40gourry.net Fixes: 75ef71840539 ("mm, vmstat: add infrastructure for per-node vmstats") Signed-off-by: Gregory Price Acked-by: David Hildenbrand (Arm) Link: https://patch.msgid.link/20260701221613.2818148-1-gourry@gourry.net Signed-off-by: Mike Rapoport (Microsoft) --- mm/memory_hotplug.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'mm/memory_hotplug.c') diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index 7ac19fab2263..8b137328dcf0 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -1263,7 +1263,8 @@ static pg_data_t *hotadd_init_pgdat(int nid) pgdat = NODE_DATA(nid); /* init node's zones as empty zones, we don't have any present pages.*/ - free_area_init_core_hotplug(pgdat); + if (free_area_init_core_hotplug(pgdat)) + return NULL; /* * The node we allocated has no zone fallback lists. For avoiding -- cgit v1.2.3