Re: [PATCH][next] futex: fix assigned ret variable that is never read

[Davidlohr Bueso]

On Wed, 18 Aug 2021, Colin King wrote:

> From: Colin Ian King <colin.king@xxxxxxxxxxxxx>
>
> Currently the check on the rt_waiter and top_waiter->pi_state is
> assigning an error return code to ret but this later gets re-assigned,
> hence the check is currently ineffective. I believe the original
> intent was to return -EINVAL rather than assign it to ret. Fix this.

LGTM.

Acked-by: Davidlohr Bueso <dbueso@xxxxxxx>

> Addresses-Coverity: ("Unused value")
> Fixes: dc7109aaa233 ("futex: Validate waiter correctly in futex_proxy_trylock_atomic()")
> Signed-off-by: Colin Ian King <colin.king@xxxxxxxxxxxxx>
> ---
> kernel/futex.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/kernel/futex.c b/kernel/futex.c
> index e7b4c6121da4..30e7daebaec8 100644
> --- a/kernel/futex.c
> +++ b/kernel/futex.c
> @@ -2025,7 +2025,7 @@ futex_proxy_trylock_atomic(u32 __user *pifutex, struct futex_hash_bucket *hb1,
> 	 * and waiting on the 'waitqueue' futex which is always !PI.
> 	 */
> 	if (!top_waiter->rt_waiter || top_waiter->pi_state)
> -		ret = -EINVAL;
> +		return -EINVAL;
>
> 	/* Ensure we requeue to the expected futex. */
> 	if (!match_futex(top_waiter->requeue_pi_key, key2))
> --
> 2.32.0