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]>
---
mm/memblock.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/mm/memblock.c b/mm/memblock.c
index 3feafea06ab2..1b8e902490e5 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -419,7 +419,7 @@ 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);
--
2.20.1
On Sat, Jun 24, 2023 at 11:26:07AM +0800, Song Shuai wrote:
> 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]>
This is queued now, it will appear in memblock/for-next after the merge
window closes.
Thanks!
> ---
> mm/memblock.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/mm/memblock.c b/mm/memblock.c
> index 3feafea06ab2..1b8e902490e5 100644
> --- a/mm/memblock.c
> +++ b/mm/memblock.c
> @@ -419,7 +419,7 @@ 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);
> --
> 2.20.1
>
>
--
Sincerely yours,
Mike.