On 01/30/24 at 06:18pm, yang.zhang wrote:
> From: "yang.zhang" <yang.zhang@xxxxxxxxxxxx>
>
> Because of alignment requirement in kexec-tools, there is
> no problem for user buffer increasing when loading segments.
> But when coping, the step is uchunk, so we should use uchunk
> not mchunk.
In theory, ubytes is <= mbytes. So uchunk is always <= mchunk. If ubytes
is exhausted, while there's still remaining mbytes, then uchunk is 0,
there's still mchunk stepping forward. If I understand it correctly,
this is a good catch. Not sure if Eric has comment on this to confirm.
static int kimage_load_normal_segment(struct kimage *image,
struct kexec_segment *segment)
{
......
ptr += maddr & ~PAGE_MASK;
mchunk = min_t(size_t, mbytes,
PAGE_SIZE - (maddr & ~PAGE_MASK));
uchunk = min(ubytes, mchunk);
......}
>
> Signed-off-by: yang.zhang <yang.zhang@xxxxxxxxxxxx>
> ---
> kernel/kexec_core.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c
> index d08fc7b5db97..2b8354313c85 100644
> --- a/kernel/kexec_core.c
> +++ b/kernel/kexec_core.c
> @@ -813,9 +813,9 @@ static int kimage_load_normal_segment(struct kimage *image,
> ubytes -= uchunk;
> maddr += mchunk;
> if (image->file_mode)
> - kbuf += mchunk;
> + kbuf += uchunk;
> else
> - buf += mchunk;
> + buf += uchunk;
> mbytes -= mchunk;
>
> cond_resched();
> @@ -881,9 +881,9 @@ static int kimage_load_crash_segment(struct kimage *image,
> ubytes -= uchunk;
> maddr += mchunk;
> if (image->file_mode)
> - kbuf += mchunk;
> + kbuf += uchunk;
> else
> - buf += mchunk;
> + buf += uchunk;
> mbytes -= mchunk;
>
> cond_resched();
> --
> 2.34.1
>
>
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