On 05/27/23 at 08:34pm, Zhen Lei wrote:
> If the value of parameter 'new_size' is in the semi-open and semi-closed
> interval (crashk_res.end - KEXEC_CRASH_MEM_ALIGN + 1, crashk_res.end], the
> calculation result of ram_res is:
> ram_res->start = crashk_res.end + 1
> ram_res->end = crashk_res.end
If the new_size is smaller than KEXEC_CRASH_MEM_ALIGN, does it make
any sense except of testing purpose? Do we need to fail this kind of
shrinking, or just shrink all the left crash memory?
> The operation of function insert_resource() fails, and ram_res is not
> added to iomem_resource. As a result, the memory of the control block
> ram_res is leaked.
>
> In fact, on all architectures, the start address and size of crashk_res
> are already aligned by KEXEC_CRASH_MEM_ALIGN. Therefore, we do not need to
> round up crashk_res.start again. Instead, we should round up 'new_size'
> in advance.
>
> Fixes: 6480e5a09237 ("kdump: add missing RAM resource in crash_shrink_memory()")
> Fixes: 06a7f711246b ("kexec: premit reduction of the reserved memory size")
> Signed-off-by: Zhen Lei <thunder.leizhen@xxxxxxxxxx>
> ---
> kernel/kexec_core.c | 5 ++---
> 1 file changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c
> index 3d578c6fefee385..22acee18195a591 100644
> --- a/kernel/kexec_core.c
> +++ b/kernel/kexec_core.c
> @@ -1122,6 +1122,7 @@ int crash_shrink_memory(unsigned long new_size)
> start = crashk_res.start;
> end = crashk_res.end;
> old_size = (end == 0) ? 0 : end - start + 1;
> + new_size = roundup(new_size, KEXEC_CRASH_MEM_ALIGN);
> if (new_size >= old_size) {
> ret = (new_size == old_size) ? 0 : -EINVAL;
> goto unlock;
> @@ -1133,9 +1134,7 @@ int crash_shrink_memory(unsigned long new_size)
> goto unlock;
> }
>
> - start = roundup(start, KEXEC_CRASH_MEM_ALIGN);
> - end = roundup(start + new_size, KEXEC_CRASH_MEM_ALIGN);
> -
> + end = start + new_size;
> crash_free_reserved_phys_range(end, crashk_res.end);
>
> if ((start == end) && (crashk_res.parent != NULL))
> --
> 2.25.1
>
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