On 11/27/23 at 10:56am, fuqiang wang wrote:
> When the split happened, judge whether mem->nr_ranges is equal to
> mem->max_nr_ranges. If it is true, return -ENOMEM.
>
> The advantage of doing this is that it can avoid array bounds caused by
> some bugs. E.g., Before commit 4831be702b95 ("arm64/kexec: Fix missing
> extra range for crashkres_low."), reserve both high and low memories for
> the crashkernel may cause out of bounds.
>
> On the other hand, move this code before the split to ensure that the
> array will not be changed when return error.
If out of array boundary is caused, means the laoding failed, whether
the out of boundary happened or not. I don't see how this code change
makes sense. Do I miss anything?
Thanks
Baoquan
>
> Signed-off-by: fuqiang wang <fuqiang.wang@xxxxxxxxxxxx>
> ---
> kernel/crash_core.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/kernel/crash_core.c b/kernel/crash_core.c
> index efe87d501c8c..ffdc246cf425 100644
> --- a/kernel/crash_core.c
> +++ b/kernel/crash_core.c
> @@ -611,6 +611,9 @@ int crash_exclude_mem_range(struct crash_mem *mem,
> }
>
> if (p_start > start && p_end < end) {
> + /* Split happened */
> + if (mem->nr_ranges == mem->max_nr_ranges)
> + return -ENOMEM;
> /* Split original range */
> mem->ranges[i].end = p_start - 1;
> temp_range.start = p_end + 1;
> @@ -626,9 +629,6 @@ int crash_exclude_mem_range(struct crash_mem *mem,
> if (!temp_range.end)
> return 0;
>
> - /* Split happened */
> - if (i == mem->max_nr_ranges - 1)
> - return -ENOMEM;
>
> /* Location where new range should go */
> j = i + 1;
> --
> 2.42.0
>
>
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