In add_memory_resource(), creation of memory block devices occurs after
successful call to arch_add_memory(). However, creation of memory block
devices could fail.  In that case, arch_remove_memory() is called to
perform necessary cleanup.

Currently with or without altmap support, arch_remove_memory() is always
passed with altmap set to NULL during error handling. This leads to
freeing of struct pages using free_pages(), eventhough the allocation
might have been performed with altmap support via
altmap_alloc_block_buf().

Fix the error handling by passing altmap in arch_remove_memory(). This
ensures the following:
* When altmap is disabled, deallocation of the struct pages array occurs
  via free_pages().
* When altmap is enabled, deallocation occurs via vmem_altmap_free().

Fixes: a08a2ae34613 ("mm,memory_hotplug: allocate memmap from the added memory range")
Reviewed-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Signed-off-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
---
 mm/memory_hotplug.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index c8238fc5edcb..4f476a970e84 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1458,7 +1458,7 @@ int __ref add_memory_resource(int nid, struct resource *res, mhp_t mhp_flags)
 	/* create memory block devices after memory was added */
 	ret = create_memory_block_devices(start, size, params.altmap, group);
 	if (ret) {
-		arch_remove_memory(start, size, NULL);
+		arch_remove_memory(start, size, params.altmap);
 		goto error_free;
 	}
 
-- 
2.41.0

On 20.11.23 08:23, Sumanth Korikkar wrote:
> In add_memory_resource(), creation of memory block devices occurs after
> successful call to arch_add_memory(). However, creation of memory block
> devices could fail.  In that case, arch_remove_memory() is called to
> perform necessary cleanup.
> 
> Currently with or without altmap support, arch_remove_memory() is always
> passed with altmap set to NULL during error handling. This leads to
> freeing of struct pages using free_pages(), eventhough the allocation
> might have been performed with altmap support via
> altmap_alloc_block_buf().
> 
> Fix the error handling by passing altmap in arch_remove_memory(). This
> ensures the following:
> * When altmap is disabled, deallocation of the struct pages array occurs
>    via free_pages().
> * When altmap is enabled, deallocation occurs via vmem_altmap_free().
> 
> Fixes: a08a2ae34613 ("mm,memory_hotplug: allocate memmap from the added memory range")
> Reviewed-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
> Signed-off-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
> ---
>   mm/memory_hotplug.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> index c8238fc5edcb..4f476a970e84 100644
> --- a/mm/memory_hotplug.c
> +++ b/mm/memory_hotplug.c
> @@ -1458,7 +1458,7 @@ int __ref add_memory_resource(int nid, struct resource *res, mhp_t mhp_flags)
>   	/* create memory block devices after memory was added */
>   	ret = create_memory_block_devices(start, size, params.altmap, group);
>   	if (ret) {
> -		arch_remove_memory(start, size, NULL);
> +		arch_remove_memory(start, size, params.altmap);
>   		goto error_free;
>   	}
>   

We should likely CC stable on this one

Acked-by: David Hildenbrand <david@redhat.com>

-- 
Cheers,

David / dhildenb