atomic_cmpxchg returns the previous value. If the previous value was 0 then it was previously unlocked and we now have acquired the lock. Thus, it should be c==0 that is considered as the case we enter the lock, not c!=0 As far as I can tell, lock_try (and lock_set_try) are currently no used anywhere in the code, so this fix shoudn't have any impact You can view, comment on, or merge this pull request online at: https://github.com/kamailio/kamailio/pull/520 -- Commit Summary -- * core/futex: fix bug in futex_try -- File Changes -- M futexlock.h (2) -- Patch Links -- https://github.com/kamailio/kamailio/pull/520.patch https://github.com/kamailio/kamailio/pull/520.diff --- Reply to this email directly or view it on GitHub: https://github.com/kamailio/kamailio/pull/520