When iterating on a linked list, a result of memremap is dereferenced
without checking it for NULL.
This patch adds a check that falls back on allocating a new page in
case memremap doesn't succeed.
Found by Linux Verification Center (linuxtesting.org) with SVACE.
Fixes: 18df7577adae ("efi/memreserve: deal with memreserve entries in unmapped memory")
Signed-off-by: Anton Gusev <aagusev@xxxxxxxxx>
---
drivers/firmware/efi/efi.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index a2b0cbc8741c..48d30c806d94 100644
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -1007,6 +1007,8 @@ int __ref efi_mem_reserve_persistent(phys_addr_t addr, u64 size)
/* first try to find a slot in an existing linked list entry */
for (prsv = efi_memreserve_root->next; prsv; ) {
rsv = memremap(prsv, sizeof(*rsv), MEMREMAP_WB);
+ if (!rsv)
+ break;
index = atomic_fetch_add_unless(&rsv->count, 1, rsv->size);
if (index < rsv->size) {
rsv->entry[index].base = addr;
--
2.39.1
