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| author | Gregory Price <gourry@gourry.net> | 2026-07-01 18:16:13 -0400 |
|---|---|---|
| committer | Mike Rapoport (Microsoft) <rppt@kernel.org> | 2026-07-02 11:54:52 +0300 |
| commit | 2ebce860bdd7ae5e13002811bc9bbbf33fcfc221 (patch) | |
| tree | 4cd03b33403129cb6b604e21f21141eb7d06824a | |
| parent | 7783dcd79ae9c4aa48bc47bd4275772445dc4b2a (diff) | |
| download | linux-next-2ebce860bdd7ae5e13002811bc9bbbf33fcfc221.tar.gz linux-next-2ebce860bdd7ae5e13002811bc9bbbf33fcfc221.zip | |
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 <sashiko-bot@kernel.org>
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 <gourry@gourry.net>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Link: https://patch.msgid.link/20260701221613.2818148-1-gourry@gourry.net
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
| -rw-r--r-- | include/linux/memory_hotplug.h | 2 | ||||
| -rw-r--r-- | mm/memory_hotplug.c | 3 | ||||
| -rw-r--r-- | mm/mm_init.c | 14 |
3 files changed, 14 insertions, 5 deletions
diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h index 7c9d66729c60..06c58cb05779 100644 --- a/include/linux/memory_hotplug.h +++ b/include/linux/memory_hotplug.h @@ -289,7 +289,7 @@ static inline void __remove_memory(u64 start, u64 size) {} /* Default online_type (MMOP_*) when new memory blocks are added. */ extern enum mmop mhp_get_default_online_type(void); extern void mhp_set_default_online_type(enum mmop online_type); -extern void __ref free_area_init_core_hotplug(struct pglist_data *pgdat); +int __ref free_area_init_core_hotplug(struct pglist_data *pgdat); extern int __add_memory(int nid, u64 start, u64 size, mhp_t mhp_flags); extern int add_memory(int nid, u64 start, u64 size, mhp_t mhp_flags); extern int add_memory_resource(int nid, struct resource *resource, 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 diff --git a/mm/mm_init.c b/mm/mm_init.c index 0d2eb82fa068..1ba1181d8ef9 100644 --- a/mm/mm_init.c +++ b/mm/mm_init.c @@ -1535,7 +1535,7 @@ void __init set_pageblock_order(void) * NOTE: this function is only called during memory hotplug */ #ifdef CONFIG_MEMORY_HOTPLUG -void __ref free_area_init_core_hotplug(struct pglist_data *pgdat) +int __ref free_area_init_core_hotplug(struct pglist_data *pgdat) { int nid = pgdat->node_id; enum zone_type z; @@ -1543,8 +1543,14 @@ void __ref free_area_init_core_hotplug(struct pglist_data *pgdat) pgdat_init_internals(pgdat); - if (pgdat->per_cpu_nodestats == &boot_nodestats) - pgdat->per_cpu_nodestats = alloc_percpu(struct per_cpu_nodestat); + if (pgdat->per_cpu_nodestats == &boot_nodestats) { + struct per_cpu_nodestat __percpu *p; + + p = alloc_percpu(struct per_cpu_nodestat); + if (!p) + return -ENOMEM; + pgdat->per_cpu_nodestats = p; + } /* * Reset the nr_zones, order and highest_zoneidx before reuse. @@ -1575,6 +1581,8 @@ void __ref free_area_init_core_hotplug(struct pglist_data *pgdat) zone->present_pages = 0; zone_init_internals(zone, z, nid, 0); } + + return 0; } #endif |