Re: [PATCH printk v1 01/18] kdb: do not assume write() callback available

[Doug Anderson]

Hi,

On Thu, Mar 2, 2023 at 11:57 AM John Ogness <john.ogness@xxxxxxxxxxxxx> wrote:
>
> It is allowed for consoles to provide no write() callback. For
> example ttynull does this.
>
> Check if a write() callback is available before using it.
>
> Signed-off-by: John Ogness <john.ogness@xxxxxxxxxxxxx>
> ---
>  kernel/debug/kdb/kdb_io.c | 2 ++
>  1 file changed, 2 insertions(+)
>
> diff --git a/kernel/debug/kdb/kdb_io.c b/kernel/debug/kdb/kdb_io.c
> index 5c7e9ba7cd6b..e9139dfc1f0a 100644
> --- a/kernel/debug/kdb/kdb_io.c
> +++ b/kernel/debug/kdb/kdb_io.c
> @@ -576,6 +576,8 @@ static void kdb_msg_write(const char *msg, int msg_len)
>                         continue;
>                 if (c == dbg_io_ops->cons)
>                         continue;
> +               if (!c->write)
> +                       continue;

Reviewed-by: Douglas Anderson <dianders@xxxxxxxxxxxx>