On Wed, 18 Dec 2024 19:42:22 +0800
Edward Adam Davis <eada...@qq.com> wrote:
> diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
> index 7e257e855dd1..20f0e01b7a50 100644
> --- a/kernel/trace/ring_buffer.c
> +++ b/kernel/trace/ring_buffer.c
> @@ -7019,7 +7019,11 @@ static int __rb_map_vma(struct ring_buffer_per_cpu
> *cpu_buffer,
> lockdep_assert_held(&cpu_buffer->mapping_lock);
>
> nr_subbufs = cpu_buffer->nr_pages + 1; /* + reader-subbuf */
> - nr_pages = ((nr_subbufs + 1) << subbuf_order) - pgoff; /* + meta-page */
> + nr_pages = ((nr_subbufs + 1) << subbuf_order); /* + meta-page */
> + if (nr_pages < pgoff)
That probably should be <= as if it was equal...
> + return -EINVAL;
> +
> + nr_pages -= pgoff;
nr_pages would be zero and
>
> nr_vma_pages = vma_pages(vma);
> if (!nr_vma_pages || nr_vma_pages > nr_pages)
this would return true, which the next line is:
return -EINVAL;
Why not catch it before going through all that?
-- Steve
> --
