kdb: delete unexecuted if-block in kdb_get_kbd_char()

[PATCH] kdb: delete unexecuted if-block in kdb_get_kbd_char()

Posted by Matvey Kovalev 2 months, 2 weeks ago

Bits of scancode are dropped except 7 low-order ones.
So, scancode can't be equal 0xe0.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Signed-off-by: Matvey Kovalev <matvey.kovalev@ispras.ru>
---
 kernel/debug/kdb/kdb_keyboard.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/kernel/debug/kdb/kdb_keyboard.c b/kernel/debug/kdb/kdb_keyboard.c
index 3a74604fdb8a7..386d30e530b78 100644
--- a/kernel/debug/kdb/kdb_keyboard.c
+++ b/kernel/debug/kdb/kdb_keyboard.c
@@ -145,9 +145,6 @@ int kdb_get_kbd_char(void)
 		return CTRL('F');
 	}
 
-	if (scancode == 0xe0)
-		return -1;
-
 	/*
 	 * For Japanese 86/106 keyboards
 	 * 	See comment in drivers/char/pc_keyb.c.
-- 
2.43.0.windows.1

Re: [PATCH] kdb: delete unexecuted if-block in kdb_get_kbd_char()

Posted by Doug Anderson 2 months, 2 weeks ago

Hi,

On Fri, Oct 3, 2025 at 8:13 AM Matvey Kovalev <matvey.kovalev@ispras.ru> wrote:
>
> Bits of scancode are dropped except 7 low-order ones.
> So, scancode can't be equal 0xe0.
>
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
>
> Signed-off-by: Matvey Kovalev <matvey.kovalev@ispras.ru>
> ---
>  kernel/debug/kdb/kdb_keyboard.c | 3 ---
>  1 file changed, 3 deletions(-)
>
> diff --git a/kernel/debug/kdb/kdb_keyboard.c b/kernel/debug/kdb/kdb_keyboard.c
> index 3a74604fdb8a7..386d30e530b78 100644
> --- a/kernel/debug/kdb/kdb_keyboard.c
> +++ b/kernel/debug/kdb/kdb_keyboard.c
> @@ -145,9 +145,6 @@ int kdb_get_kbd_char(void)
>                 return CTRL('F');
>         }
>
> -       if (scancode == 0xe0)
> -               return -1;
> -

The same patch has already been sent and was landed:

https://lore.kernel.org/all/20250507104337.201695-1-colin.i.king@gmail.com/

Re: [PATCH] kdb: delete unexecuted if-block in kdb_get_kbd_char()

Posted by matvey.kovalev@ispras.ru 2 months, 1 week ago

Doug Anderson писал(а) 2025-10-03 19:39:
> The same patch has already been sent and was landed:
> 
> https://lore.kernel.org/all/20250507104337.201695-1-colin.i.king@gmail.com/
Тhanks for information!

--
Matvey Kovalev