On Fri, Sep 04, 2026 at 02:49:02PM -0400, Steven Rostedt wrote:
> From: Steven Rostedt <[email protected]>
> 
> The comment about returning an error if the read fails on the first
> iteration is slightly incorrect. It makes it sound like the only reason it
> could fail on a later iteration is if the subbuf order changed. That is
> incorrect, it could also fail if the length passed in was not a multiple
> of the subbuf size. Fix the comment.
> 
> Link: https://lore.kernel.org/all/[email protected]/
> Fixes: TBD
> Signed-off-by: Steven Rostedt <[email protected]>
> ---
>  kernel/trace/trace.c | 12 +++++++-----
>  1 file changed, 7 insertions(+), 5 deletions(-)
> 
> diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
> index b26c4c277ce5..8658cad53cb5 100644
> --- a/kernel/trace/trace.c
> +++ b/kernel/trace/trace.c
> @@ -7296,11 +7296,13 @@ ssize_t tracing_buffers_splice_read(struct file 
> *file, loff_t *ppos,
>                       r = ring_buffer_read_page(ref->buffer, ref->rpage, len, 
> iter->cpu_file, 1);
>               } else if (!i) {
>                       /*
> -                      * We failed to read because the length is too small
> -                      * or unaligned. If this is the first iteration, it's
> -                      * an invalid userspace input. Otherwise, this is due
> -                      * to a subbuf order change. Do not report an error
> -                      * and just finish the read.
> +                      * If this fails to read on the first iteration, it
> +                      * means the length was too small and an error should
> +                      * be returned to user space. Otherwise, at least
> +                      * one sub-buffer was successfully read but this failed
> +                      * due to either the length was unaligned or the
> +                      * subbuf order changed. Either case, do not report
> +                      * an error.
>                        */
>                       ret = -EINVAL;
>               }
> -- 
> 2.53.0
> 

Ha yes, I see the missing case you were refering to now.

Reviewed-by: Vincent Donnefort <[email protected]>

-- 
Vincent

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