Re: [PATCH v2] kdb: Replace deprecated strcpy() with memmove() in vkdb_printf()

[Daniel Thompson <daniel@riscstar.com>]

On Tue, Aug 12, 2025 at 09:24:55AM -0700, Doug Anderson wrote:
> Hi,
>
> On Tue, Aug 12, 2025 at 6:27 AM Thorsten Blum <thorsten.blum@linux.dev> wrote:
> >
> > strcpy() is deprecated and its behavior is undefined when the source and
> > destination buffers overlap. Use memmove() instead to avoid any
> > undefined behavior.
> >
> > Adjust comments for clarity.
> >
> > Link: https://github.com/KSPP/linux/issues/88
> > Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
> > ---
> > Changes in v2:
> > - Use memmove() because of strcpy()'s undefined behavior with
> >   overlapping buffers as suggested by Doug Anderson
> > - Compile-tested only
> > - Link to v1: https://lore.kernel.org/lkml/20250811170351.68985-1-thorsten.blum@linux.dev/
> > ---
> >  kernel/debug/kdb/kdb_io.c | 14 ++++++++------
> >  1 file changed, 8 insertions(+), 6 deletions(-)
>
> Much nicer, thank you!
>
> Given that the old code was officially relying on undefined behavior
> of strcpy() before, I'd personally even add:
>
> Fixes: 5d5314d6795f ("kdb: core for kgdb back end (1 of 2)")
>
> In any case:
>
> Reviewed-by: Douglas Anderson <dianders@chromium.org>

LGTM... and I agree that this is bug rather than a clean up so am
waiting to hear back on the Fixes: .


Daniel


PS Feel free to roll all three kdb patches discussed recently into a
   series so I can pull in one go ;-) .