[PATCH 2/8] mm/memory_hotplug: fix error handling in add_memory_resource()

Sumanth Korikkar
2023-11-14T18:03:06Z

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: db051a0dac13 ("mm/memory_hotplug: create memory block devices after arch_add_memory()")
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