memblock: use kfree() to release kmalloced memblock regions

stable inclusion
from linux-4.19.232
commit a6fcced73d15ab57cd97813999edf6f19d3032f8

--------------------------------

commit c94afc46 upstream.

memblock.{reserved,memory}.regions may be allocated using kmalloc() in
memblock_double_array(). Use kfree() to release these kmalloced regions
indicated by memblock_{reserved,memory}_in_slab.
Signed-off-by: NMiaohe Lin <linmiaohe@huawei.com>
Fixes: 3010f876 ("mm: discard memblock data later")
Signed-off-by: NMike Rapoport <rppt@linux.ibm.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NYongqiang Liu <liuyongqiang13@huawei.com>
Signed-off-by: NLaibin Qiu <qiulaibin@huawei.com>

mm/memblock.c

@@ -330,14 +330,20 @@ void __init memblock_discard(void)
 		addr = __pa(memblock.reserved.regions);
 		size = PAGE_ALIGN(sizeof(struct memblock_region) *
 				  memblock.reserved.max);
-		__memblock_free_late(addr, size);
+		if (memblock_reserved_in_slab)
+			kfree(memblock.reserved.regions);
+		else
+			__memblock_free_late(addr, size);
 	}
 
 	if (memblock.memory.regions != memblock_memory_init_regions) {
 		addr = __pa(memblock.memory.regions);
 		size = PAGE_ALIGN(sizeof(struct memblock_region) *
 				  memblock.memory.max);
-		__memblock_free_late(addr, size);
+		if (memblock_memory_in_slab)
+			kfree(memblock.memory.regions);
+		else
+			__memblock_free_late(addr, size);
 	}
 }
 #endif