memblock: report failures when memblock_can_resize is not set

The callers of memblock_reserve() do not check the return value
presuming that memblock_reserve() always succeeds, but there are
cases where it may fail.

Having numerous memblock reservations at early boot where
memblock_can_resize is unset may exhaust the INIT_MEMBLOCK_REGIONS sized
memblock.reserved regions array and an attempt to double this array via
memblock_double_array() will fail and will return -1 to the caller.

When this happens the system crashes anyway, but it's hard to identify
the reason for the crash.

Add a panic message to memblock_double_array() to aid debugging of the
cases when too many regions are reserved before memblock can resize
memblock.reserved array.

Link: https://lore.kernel.org/linux-kernel/[email protected]/
Signed-off-by: Song Shuai <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Mike Rapoport (IBM) <[email protected]>

diff --git a/mm/memblock.c b/mm/memblock.c
index 913b2520a9a002095349e3b27618ff5d97ded41c..0863222af4a481f5f05dd9a42ac12ff9b1478481 100644 (file)
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -424,7 +424,7 @@ static int __init_memblock memblock_double_array(struct memblock_type *type,
         * of memory that aren't suitable for allocation
         */
        if (!memblock_can_resize)
-               return -1;
+               panic("memblock: cannot resize %s array\n", type->name);
 
        /* Calculate new doubled size */
        old_size = type->max * sizeof(struct memblock_region);