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

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

[Colin King]

From: Colin Ian King <colin.king@canonical.com>

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.

Addresses-Coverity: ("Unused value")
Fixes: dc7109aaa233 ("futex: Validate waiter correctly in futex_proxy_trylock_atomic()")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
 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

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

[André Almeida]

Hi Colin,

Às 10:18 de 18/08/21, Colin King escreveu:
> From: Colin Ian King <colin.king@canonical.com>
> 
> 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.
> 
> Addresses-Coverity: ("Unused value")
> Fixes: dc7109aaa233 ("futex: Validate waiter correctly in futex_proxy_trylock_atomic()")
> Signed-off-by: Colin Ian King <colin.king@canonical.com>> ---

Reviewed-by: André Almeida <andrealmeid@collabora.com>

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@canonical.com>
>
>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@suse.de>

>
>Addresses-Coverity: ("Unused value")
>Fixes: dc7109aaa233 ("futex: Validate waiter correctly in futex_proxy_trylock_atomic()")
>Signed-off-by: Colin Ian King <colin.king@canonical.com>
>---
> 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
>