* [PATCH] memblock: report failures when memblock_can_resize is not set
@ 2023-06-24 3:26 Song Shuai
2023-06-28 7:33 ` Mike Rapoport
0 siblings, 1 reply; 2+ messages in thread
From: Song Shuai @ 2023-06-24 3:26 UTC (permalink / raw)
To: rppt, akpm; +Cc: linux-mm, linux-kernel, Song Shuai
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/20230614131746.3670303-1-songshuaishuai@tinylab.org/
Signed-off-by: Song Shuai <songshuaishuai@tinylab.org>
---
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
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] memblock: report failures when memblock_can_resize is not set
2023-06-24 3:26 [PATCH] memblock: report failures when memblock_can_resize is not set Song Shuai
@ 2023-06-28 7:33 ` Mike Rapoport
0 siblings, 0 replies; 2+ messages in thread
From: Mike Rapoport @ 2023-06-28 7:33 UTC (permalink / raw)
To: Song Shuai; +Cc: akpm, linux-mm, linux-kernel
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/20230614131746.3670303-1-songshuaishuai@tinylab.org/
> Signed-off-by: Song Shuai <songshuaishuai@tinylab.org>
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.
^ permalink raw reply [flat|nested] 2+ messages in thread
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