Hello,

I've just finished migrating a project from GDC/Makefile to LDC with dub. The program now compiles and runs, and works fine until such time as the following error occurs:

Aborting from core/sync/mutex.d(147) Error: pthread_mutex_init failed.

out of GDB, the whole text is:

Aborting from core/sync/mutex.d(147) Error: pthread_mutex_init failed.
Thread 1 "squares" received signal SIGABRT, Aborted.
[Switching to Thread 0x7ffff74a7580 (LWP 7576)]
__GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:50
50	../sysdeps/unix/sysv/linux/raise.c: No such file or directory.

and the backtrace is (sorry for info dump):

#0  __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:50
#1  0x00007ffff76eb535 in __GI_abort () at abort.c:79
#2  0x00007ffff7ac4fa7 in _D4core8internal5abortQgFNbNiNfMAyaMQemZv ()
   from /lib/x86_64-linux-gnu/libdruntime-ldc-shared.so.82
#3  0x00007ffff7acd7e3 in core.sync.mutex.Mutex.~this() ()
   from /lib/x86_64-linux-gnu/libdruntime-ldc-shared.so.82
#4  0x00007ffff7af12ae in rt_finalize2 () from /lib/x86_64-linux-gnu/libdruntime-ldc-shared.so.82
#5  0x00007ffff7adb7bf in _D2gc4impl12conservativeQw3Gcx5sweepMFNbZm ()
   from /lib/x86_64-linux-gnu/libdruntime-ldc-shared.so.82
#6  0x00007ffff7ad89b2 in _D2gc4impl12conservativeQw3Gcx11fullcollectMFNbbZm ()
   from /lib/x86_64-linux-gnu/libdruntime-ldc-shared.so.82
#7  0x00007ffff7ada126 in _D2gc4impl12conservativeQw3Gcx10smallAllocMFNbhKmkZPv ()
   from /lib/x86_64-linux-gnu/libdruntime-ldc-shared.so.82
#8  0x00007ffff7ad6c44 in _D2gc4impl12conservativeQw14ConservativeGC__T9runLockedS_DQCeQCeQCcQCnQBs12mallocNoSyncMFNbmkKmxC8TypeInfoZPvS_DQEgQEgQEeQEp10mallocTimelS_DQFiQFiQFgQFr10numMallocslTmTkTmTxQCzZQFcMFNbKmKkKmKxQDsZQDl () from /lib/x86_64-linux-gnu/libdruntime-ldc-shared.so.82
#9  0x00007ffff7ad92df in _DThn16_2gc4impl12conservativeQw14ConservativeGC6qallocMFNbmkxC8TypeInfoZS4core6memory8BlkInfo_ () from /lib/x86_64-linux-gnu/libdruntime-ldc-shared.so.82
#10 0x00007ffff7addbd0 in gc_qalloc () from /lib/x86_64-linux-gnu/libdruntime-ldc-shared.so.82
#11 0x00007ffff7ac9fb2 in _D4core6memory2GC6qallocFNaNbmkxC8TypeInfoZSQBqQBo8BlkInfo_ ()
   from /lib/x86_64-linux-gnu/libdruntime-ldc-shared.so.82
#12 0x00007ffff7af0519 in _d_newarrayU () from /lib/x86_64-linux-gnu/libdruntime-ldc-shared.so.82
#13 0x00005555556b9682 in _D7squares4core5coord5Coord9adjacentsMxFNdZASQBrQBmQBkQBh (this=...)
    at /home/mitchell/Apps/D/games/squares/src/squares/core/coord.d:102

There are several frames above #13 here, but #13 is the last line of "my" code, and the deeper ones (appear?) to be runtime and phobos stuff.The lines immediately around coord.d:102 are:

    Coord[] adjacents() const @property
    {
        return [ right, up, left, down ]; // line 102
    }

which are defined in a struct called "Coord". I suspect that there isn't something wrong specifically with this line, and instead something more "amazingly" wrong. Given that this worked fine with the previous (and older) version of GDC which I used before my migration, I don't know what could be wrong.

I'm just not entirely certain where to start looking for problems. If this issue is over-broad, I'm sorry. Elsewhere in the program, I make use of the core.thread and Thread things, however that implementation seems fairly straightforward and fine, and never had issues under the old compiler.

Any and all help is appreciated!

On Wednesday, 1 April 2020 at 02:08:09 UTC, mitchell wrote:
> Hello,
>
> I've just finished migrating a project from GDC/Makefile to LDC with dub. The program now compiles and runs, and works fine until such time as the following error occurs:
>
> Aborting from core/sync/mutex.d(147) Error: pthread_mutex_init failed.
>
> out of GDB, the whole text is:
>
> Aborting from core/sync/mutex.d(147) Error: pthread_mutex_init failed.
> Thread 1 "squares" received signal SIGABRT, Aborted.
> [Switching to Thread 0x7ffff74a7580 (LWP 7576)]
> __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:50
> 50	../sysdeps/unix/sysv/linux/raise.c: No such file or directory.
>
> and the backtrace is (sorry for info dump):
>
> #0  __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:50
> #1  0x00007ffff76eb535 in __GI_abort () at abort.c:79
> #2  0x00007ffff7ac4fa7 in _D4core8internal5abortQgFNbNiNfMAyaMQemZv ()
>    from /lib/x86_64-linux-gnu/libdruntime-ldc-shared.so.82
> #3  0x00007ffff7acd7e3 in core.sync.mutex.Mutex.~this() ()
>    from /lib/x86_64-linux-gnu/libdruntime-ldc-shared.so.82
> #4  0x00007ffff7af12ae in rt_finalize2 () from /lib/x86_64-linux-gnu/libdruntime-ldc-shared.so.82
> #5  0x00007ffff7adb7bf in _D2gc4impl12conservativeQw3Gcx5sweepMFNbZm ()
>    from /lib/x86_64-linux-gnu/libdruntime-ldc-shared.so.82
> #6  0x00007ffff7ad89b2 in _D2gc4impl12conservativeQw3Gcx11fullcollectMFNbbZm ()
>    from /lib/x86_64-linux-gnu/libdruntime-ldc-shared.so.82
> #7  0x00007ffff7ada126 in _D2gc4impl12conservativeQw3Gcx10smallAllocMFNbhKmkZPv ()
>    from /lib/x86_64-linux-gnu/libdruntime-ldc-shared.so.82
> #8  0x00007ffff7ad6c44 in _D2gc4impl12conservativeQw14ConservativeGC__T9runLockedS_DQCeQCeQCcQCnQBs12mallocNoSyncMFNbmkKmxC8TypeInfoZPvS_DQEgQEgQEeQEp10mallocTimelS_DQFiQFiQFgQFr10numMallocslTmTkTmTxQCzZQFcMFNbKmKkKmKxQDsZQDl () from /lib/x86_64-linux-gnu/libdruntime-ldc-shared.so.82
> #9  0x00007ffff7ad92df in _DThn16_2gc4impl12conservativeQw14ConservativeGC6qallocMFNbmkxC8TypeInfoZS4core6memory8BlkInfo_ () from /lib/x86_64-linux-gnu/libdruntime-ldc-shared.so.82
> #10 0x00007ffff7addbd0 in gc_qalloc () from /lib/x86_64-linux-gnu/libdruntime-ldc-shared.so.82
> #11 0x00007ffff7ac9fb2 in _D4core6memory2GC6qallocFNaNbmkxC8TypeInfoZSQBqQBo8BlkInfo_ ()
>    from /lib/x86_64-linux-gnu/libdruntime-ldc-shared.so.82
> #12 0x00007ffff7af0519 in _d_newarrayU () from /lib/x86_64-linux-gnu/libdruntime-ldc-shared.so.82
> #13 0x00005555556b9682 in _D7squares4core5coord5Coord9adjacentsMxFNdZASQBrQBmQBkQBh (this=...)
>     at /home/mitchell/Apps/D/games/squares/src/squares/core/coord.d:102
>
> There are several frames above #13 here, but #13 is the last line of "my" code, and the deeper ones (appear?) to be runtime and phobos stuff.The lines immediately around coord.d:102 are:
>
>     Coord[] adjacents() const @property
>     {
>         return [ right, up, left, down ]; // line 102
>     }
>
> which are defined in a struct called "Coord". I suspect that there isn't something wrong specifically with this line, and instead something more "amazingly" wrong. Given that this worked fine with the previous (and older) version of GDC which I used before my migration, I don't know what could be wrong.
>
> I'm just not entirely certain where to start looking for problems. If this issue is over-broad, I'm sorry. Elsewhere in the program, I make use of the core.thread and Thread things, however that implementation seems fairly straightforward and fine, and never had issues under the old compiler.
>
> Any and all help is appreciated!

I have (surprisingly) figured out the issue myself. I guess I didn't think about this before, but the background thread (elsewhere in the application) keeps a few mutexes such that it can pass work to the main thread (for changing UI things, and such) and it appears that after the background task is completed, there is at least one mutex which was still held in a locked state. The error arises (as can been seen from the stack trace) when that mutex is being destructed. As my underlying system is unix, the pthread object beneath mutex is destroyed, but according to the documentation (https://linux.die.net/man/3/pthread_mutex_destroy) destroying a mutex while it's still locked can cause an error. After I fixed my implementation to ensure that all mutexes are unlocked on the appropriate threads before they can be destructed, the issue went away. Apparently my old compiler either handled that issue for me automatically, or it just wasn't being detected.

TLDR: pebkac