On Thu, May 11, 2023 at 11:52:45AM -0700, Dmitry Torokhov wrote:
> When aborting PS/2 command the kernel should [re]set all flags before
> waking up waiters, otherwise waiting thread may read obsolete values
> of flags.
>
> Reported-by: Raul Rangel <rrangel@xxxxxxxxxxxx>
> Signed-off-by: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx>
> ---
> drivers/input/serio/libps2.c | 15 +++++++++++----
> 1 file changed, 11 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/input/serio/libps2.c b/drivers/input/serio/libps2.c
> index 14b70a78875d..09eb605364bb 100644
> --- a/drivers/input/serio/libps2.c
> +++ b/drivers/input/serio/libps2.c
> @@ -478,15 +478,22 @@ bool ps2_handle_response(struct ps2dev *ps2dev, u8 data)
> }
> EXPORT_SYMBOL(ps2_handle_response);
>
> +/*
> + * Clears state of PS/2 device after communication error by resetting majority
> + * of flags and waking up waiters, if any.
> + */
> void ps2_cmd_aborted(struct ps2dev *ps2dev)
> {
> - if (ps2dev->flags & PS2_FLAG_ACK)
> + unsigned long old_flags = ps2dev->flags;
> +
> + /* reset all flags except last nak */
> + ps2dev->flags &= PS2_FLAG_NAK;
> +
> + if (old_flags & PS2_FLAG_ACK)
> ps2dev->nak = 1;
>
> - if (ps2dev->flags & (PS2_FLAG_ACK | PS2_FLAG_CMD))
> + if (old_flags & (PS2_FLAG_ACK | PS2_FLAG_CMD))
> wake_up(&ps2dev->wait);
>
> - /* reset all flags except last nack */
> - ps2dev->flags &= PS2_FLAG_NAK;
> }
> EXPORT_SYMBOL(ps2_cmd_aborted);
Reviewed-by: Raul E Rangel <rrangel@xxxxxxxxxxxx>
