c1e2f0eaf015fb: "futex: Avoid violating the 10th rule of futex" seems to
make up a few new rules to violate.

Coverity picked up these two problems in the same code:


First it or's a value with stack garbage.

_______________________________________________________________________________________________________
*** CID 1427826:  Uninitialized variables  (UNINIT)
/kernel/futex.c: 2316 in fixup_pi_state_owner()
2310     
2311            raw_spin_lock_irq(&pi_state->pi_mutex.wait_lock);
2312     
2313            oldowner = pi_state->owner;
2314            /* Owner died? */
2315            if (!pi_state->owner)
>>>     CID 1427826:  Uninitialized variables  (UNINIT)
>>>     Using uninitialized value "newtid".
2316                    newtid |= FUTEX_OWNER_DIED;
2317     
2318            /*
2319             * We are here because either:
2320             *
2321             *  - we stole the lock and pi_state->owner needs updating to 
reflect

Then it notices that value is never read from before it's written
anyway.

*** CID 1427824:  Code maintainability issues  (UNUSED_VALUE)
/kernel/futex.c: 2316 in fixup_pi_state_owner()
2310     
2311            raw_spin_lock_irq(&pi_state->pi_mutex.wait_lock);
2312     
2313            oldowner = pi_state->owner;
2314            /* Owner died? */
2315            if (!pi_state->owner)
>>>     CID 1427824:  Code maintainability issues  (UNUSED_VALUE)
>>>     Assigning value from "newtid | 0x40000000U" to "newtid" here, but that 
>>> stored value is overwritten before it can be used.
2316                    newtid |= FUTEX_OWNER_DIED;
2317     
2318            /*
2319             * We are here because either:
2320             *
2321             *  - we stole the lock and pi_state->owner needs updating to 
reflect


(The next reference of newtid being..

2369         newtid = task_pid_vnr(newowner) | FUTEX_WAITERS;


        Dave

Reply via email to