futex: Return error code instead of assigning it without effect

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
ineffective.

Return -EINVAL rather than assigning it to ret which was the original
intent.

Fixes: dc7109aaa233 ("futex: Validate waiter correctly in futex_proxy_trylock_atomic()")
Addresses-Coverity: ("Unused value")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: André Almeida <andrealmeid@collabora.com>
Link: https://lore.kernel.org/r/20210818131840.34262-1-colin.king@canonical.com

diff --git a/kernel/futex.c b/kernel/futex.c
index e7b4c61..30e7dae 100644 (file)
--- 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))