On 05/27/23 at 08:34pm, Zhen Lei wrote:
> The check '(crashk_res.parent != NULL)' is added by
> commit e05bd3367bd3 ("kexec: fix Oops in crash_shrink_memory()"), but it's
> stale now. Because if 'crashk_res' is not reserved, it will be zero in
> size and will be intercepted by the above 'if (new_size >= old_size)'.
>
> Ago:
> if (new_size >= end - start + 1)
>
> Now:
> old_size = (end == 0) ? 0 : end - start + 1;
> if (new_size >= old_size)
Hmm, I would strongly suggest we keep that check. Even though the
current code like above can do the acutal checking, but its actual usage
is not obvious for checking of crashk_res existence. In the future,
someone may change above calculation and don't notice the hidden
functionality at all behind the calculation. The cost of the check is
almost zero, right?
>
> Signed-off-by: Zhen Lei <thunder.leizhen@xxxxxxxxxx>
> ---
> kernel/kexec_core.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c
> index 22acee18195a591..d1ab139dd49035e 100644
> --- a/kernel/kexec_core.c
> +++ b/kernel/kexec_core.c
> @@ -1137,7 +1137,7 @@ int crash_shrink_memory(unsigned long new_size)
> end = start + new_size;
> crash_free_reserved_phys_range(end, crashk_res.end);
>
> - if ((start == end) && (crashk_res.parent != NULL))
> + if (start == end)
> release_resource(&crashk_res);
>
> ram_res->start = end;
> --
> 2.25.1
>
_______________________________________________
kexec mailing list
kexec@xxxxxxxxxxxxxxxxxxx
http://lists.infradead.org/mailman/listinfo/kexec
