On Thu, May 18, 2017 at 01:43:23PM +0200, Peter Zijlstra wrote: > On Thu, May 18, 2017 at 10:34:34AM +0200, Florian Weimer wrote: > > On 05/18/2017 10:31 AM, Peter Zijlstra wrote: > > > > But it does that after building the tst-robustpi8 thing, so I seem to > > > have all I need here. > > > > Great, have fun figuring out what's going on. :-/ > > > > ld-linux-x86-64-2165 [018] .... 290.235869: sched_process_fork: > comm=ld-linux-x86-64 pid=2165 child_comm=ld-linux-x86-64 child_pid=2166 > ld-linux-x86-64-2166 [019] .... 290.436398: handle_futex_death: > 00007f066634e870: 876 -> 40000000 > ld-linux-x86-64-2166 [019] .... 290.436399: handle_futex_death: > 00007f066634e0c8: 876 -> 40000000 > ld-linux-x86-64-2166 [019] .... 290.436400: handle_futex_death: > 00007f066634ee38: 80000876 -> c0000000 > ld-linux-x86-64-2166 [019] .... 290.436401: sched_process_exit: > comm=ld-linux-x86-64 pid=2166 prio=120 > ld-linux-x86-64-2164 [019] ...1 290.436546: attach_to_pi_owner: 2: > 00007f066634e078 = 80000876 > > > > > ld-linux-x86-64-2183 [026] .... 827.987914: sched_process_fork: > comm=ld-linux-x86-64 pid=2183 child_comm=ld-linux-x86-64 child_pid=2187 > ld-linux-x86-64-2187 [029] .... 828.188218: handle_futex_death: > 00007f76dd361690: 88b -> 40000000 > ld-linux-x86-64-2187 [029] .... 828.188219: handle_futex_death: > 00007f76dd361898: 8000088b -> c0000000 > ld-linux-x86-64-2187 [029] .... 828.188220: handle_futex_death: > 00007f76dd3615c8: 8000088b -> c0000000 > ld-linux-x86-64-2187 [029] .... 828.188220: handle_futex_death: > 00007f76dd3612d0: 8000088b -> c0000000 > ld-linux-x86-64-2187 [029] .... 828.188220: handle_futex_death: > 00007f76dd361af0: 8000088b -> c0000000 > ld-linux-x86-64-2187 [029] .... 828.188221: handle_futex_death: > 00007f76dd361168: 8000088b -> c0000000 > ld-linux-x86-64-2187 [029] .... 828.188222: sched_process_exit: > comm=ld-linux-x86-64 pid=2187 prio=120 > ld-linux-x86-64-2182 [019] ...1 828.188373: attach_to_pi_owner: 2: > 00007f76dd361000 = 8000088b > > > > In both cases we fail in FUTEX_LOCK_PI trying to acquire a futex owned > by a dead task, resulting in the -ESRCH. > > Now, pthread_mutex_lock() isn't expecting -ESRCH for robust futexes, > because for robust we'd expect handle_futex_death() to clear out the > futex value and set OWNER_DIED, as can be seen above. > > The problem is however that the futex address we fail on, doesn't appear > to have been fixed up, so its either not on the robust list, or the > robust list got broken.
The robust list walk finishes without issue. So no premature terminations. The address really isn't on it.
