[PATCH 5.4 3/5] memblock: ensure there is no overflow in memblock_overlaps_region()

[Mark-PK Tsai]

From: Mike Rapoport <rppt@xxxxxxxxxxxxx>

commit 023accf5cdc1e504a9b04187ec23ff156fe53d90 upstream.

There maybe an overflow in memblock_overlaps_region() if it is called with
base and size such that

	base + size > PHYS_ADDR_MAX

Make sure that memblock_overlaps_region() caps the size to prevent such
overflow and remove now duplicated call to memblock_cap_size() from
memblock_is_region_reserved().

Signed-off-by: Mike Rapoport <rppt@xxxxxxxxxxxxx>
Tested-by: Tony Lindgren <tony@xxxxxxxxxxx>
Link: https://lore.kernel.org/lkml/20210630071211.21011-1-rppt@xxxxxxxxxx/
Signed-off-by: Mark-PK Tsai <mark-pk.tsai@xxxxxxxxxxxx>
---
 mm/memblock.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/mm/memblock.c b/mm/memblock.c
index 4de2af293f47..e13003ed6ee7 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -164,6 +164,8 @@ bool __init_memblock memblock_overlaps_region(struct memblock_type *type,
 {
 	unsigned long i;
 
+	memblock_cap_size(base, &size);
+
 	for (i = 0; i < type->cnt; i++)
 		if (memblock_addrs_overlap(base, size, type->regions[i].base,
 					   type->regions[i].size))
@@ -1764,7 +1766,6 @@ bool __init_memblock memblock_is_region_memory(phys_addr_t base, phys_addr_t siz
  */
 bool __init_memblock memblock_is_region_reserved(phys_addr_t base, phys_addr_t size)
 {
-	memblock_cap_size(base, &size);
 	return memblock_overlaps_region(&memblock.reserved, base, size);
 }
 
-- 
2.18.0